Physics of fundamental Symmetries and Interactions - PSI2010

10 Oct 2010, 17:00 → 14 Oct 2010, 18:30 Europe/Zurich

Main Auditorium (WHGA/001) (PSI)

Anita Van Loon-Govaerts (PSI), Bernhard Lauss (PSI), Klaus Kirch (ETHZ & PSI), Stefan Ritt (PSI)

The workshop focuses on the physics at the low energy, high precision frontier without neglecting complementary approaches. It aims at highlighting present activities and future developments. The Paul Scherrer Institut (PSI) itself offers unique opportunities for experiments in this realm: it houses the world's most powerful proton cyclotron and the highest intensity low momentum pion and muon beams. Moreover, in 2010, the high intensity ultracold neutron source will start its operation.

Workshop Home Page Workshop Home Page

Sunday 10 October

Registration

1 Registration

Welcome Apero

2 Welcome Apero

Monday 11 October

Session Mo - 1

3 Organizational

Speaker: Klaus Kirch

Slides Mo1-1-kirch.ppt

4 Welcome

Speaker: Joel Mesot (PSI - director)

5 Welcome

Speaker: Kurt Clausen (Head of NUM Department)

Slides Mo1-1-clausen.ppt

6 How to look at low energy precision physics in the era of LHC

Speaker: Daniel Wyler

7 Final results for the muon decay parameters from TWIST

Muon decay offers an opportunity to test the Standard Model of particle physics in a purely leptonic situation where more ambiguous strong interaction processes are absent. The TRIUMF Weak Interaction Symmetry Test (TWIST) was designed specifically to improve by an order of magnitude the precision of the decay parameters $\rho$, $\delta$, and $P_{\mu}\xi$ derived from energy and angle distributions of positrons from polarized positive muon decay. It tests the V-A structure of muon decay by comparing the parameters to those predicted by the Standard Model in an analysis permitting more general Lorentz-invariant local terms. Data taking was completed in 2007. The subsequent blind analysis has focused on reducing systematic uncertainties, estimating residual biases, and evaluating consistency checks. The results, dominated by the systematic uncertainties, have been further scrutinized for self-consistency. The talk will describe the experimental apparatus and analysis procedures, with particular attention to the reduction of leading systematic uncertainties. The final results and their uncertainties will be presented along with implications for physics beyond the Standard Model.

Speaker: Dr Glen Marshall (TRIUMF)

Slides marshall-psi2010.pdf

8 Muon physics programs at J-PARC

Japan Proton Accelerator Research Complex (J-PARC) has recently started its operation and a wide variety of physics programs using muon, pion, neutrino, and kaon are starting. We present latest activities of muon physics programs at J-PARC with a focus on lepton-flavor violation search experiments.

Speaker: Dr Satoshi Mihara (KEK)

Slides PSI2010-mihara.pdf

Coffee Break

Session Mo - 2

9 Particle Physics Experiments with Slow Neutrons

Experiments with slow neutrons allow to test the Standard Model of particle physics and theories of gravitation. I will review recent experiments, in particular neutron decay studies, and compare cold and ultracold neutrons.

Speaker: Torsten Soldner (ILL)

Slides PSI2010Soldner.pdf

10 UCN magnetic trapping and neutron lifetime measurements.

Precision measurements of the neutron lifetime provide stringent tests of the standard electroweak model as well as crucial inputs for tests of Big-Bang nucleosynthesis. The present world average of the neutron lifetime is dominated by results obtained using material bottles for UCNs. This average does not include a recent measurement performed at ILL which produced a value that is 6.5 standard deviations away from the world average and 5.6 standard deviations from the previously most precise measurement. Since the two most precise results for the neutron lifetime were obtained using trapped UCN in material bottles, the large discrepancy between the values indicate that systematic effects are not fully under control. New alternative measuring techniques are then called for. A prototype of a magneto-gravitational trap has been successfully tested at ILL during last years and a value of the neutron lifetime has been obtained with a statistical precision of 1.8 s. The main features and advantages of experimental setup are discussed. A trap of larger volume is presently being designed to improve the statistical precision.

Speaker: Dr Victor Ezhov (Petersburg Nuclear Physics Institute RAS)

11 PENELOPE, ON THE WAY TOWARDS A NEW PRECISE NEUTRON LIFETIME MEASUREMENT

A precise knowledge of neutron lifetime opens the way to determine the coupling constants of weak interaction precisely and hence the element Vud of the Cabibbo-Kobayashi-Maskawa matrix. Hence, measurements of the lifetime provide direct tests of the standard model of particle physics. Moreover, the neutron lifetime is important for astrophysical models, especially Big Bang nucleosynthesis. The most successful measurements have been made storing ultra-cold neutrons (UCN) that have energies of only a few hundred neV. However, a recent result from a UCN trapping experiment [1] disagrees with the PDG average of 885.7±0.8 s by roughly 6 standard deviations. To resolve this discrepancy, we are developing an experiment with a superconducting magnetic trap for UCN at Technische Universität München, Physik Department E18. These UCN will be trapped in a multipole field of a flux density up to 2 T and will be bound by the gravitational potential to the top. This makes the extraction and detection of the decay protons (and electrons) possible and allows a direct measurement of the neutron decay rate. Our envisaged precision of < 0.1 s demands almost lossless storage and good knowledge of systematic errors; these could result from e.g. neutron spin flip or high energetic UCN that leave the storage volume only slowly. Therefore, the neutron spectrum is cleaned by an absorber. The big storage volume of 750 liters and the expected high neutron flux of the UCN source at the FRMII give more than 10e7 neutrons per filling of the trap. This shall allow us to concentrate on systematic effects, as the necessary statistics is reached within days; a crucial point for this kind of experiments. The talk will motivate the measurement, desribe it in detail, present simulations and discuss systematic effects and investigations. [1] A. Serebrov et al. Phys. Lett. B, 605:72–78, 2005.

Speaker: Dr Ruediger Picker (TU Muenchen Physik Department E18)

Slides PENeLOPE-PSIrev1.ppt PENeLOPE-PSIrev1.pptx

Video

• electrons.avi
• protons.avi
• psr0737-3039.avi

12 The neutron lifetime from a new evaluation of UCN storage experiments

The analysis of the data on measurements of the neutron lifetime is presented. A new most accurate result of the measurement of neutron lifetime [Phys. Lett. B 605, 72 (2005)] 878.5 ± 0.8 s differs from the world average value [Phys. Lett. B 667, 1 (2008)] 885.7 ± 0.8 s by 6.5 standard deviations. In this connection the analysis and Monte Carlo simulation of experiments [Phys. Lett. B 483, 15 (2000)] and [Phys. Rev. Lett. 63, 593 (1989)] is carried out. Systematic errors of about -6 s are found in each of the experiments. The summary table for the neutron lifetime measurements after corrections and additions is given. A new world average value for the neutron lifetime 879.9 ± 0.9 s is presented.

Speaker: Mr Alexey Fomin (Petersburg Nuclear Physics Institute)

Slides A.Fomin_PSI2010.ppt

13 COMMERCIAL WATER HOSES TO TRANSPORT ULTRACOLD AND VERY COLD NEUTRONS* AND THEIR APPLICATION IN A RECENT NEUTRON LIFETIME EXPERIMENT

Commercial water hoses with 6 to 8 mm inner diameter (flexible tubes made of a polyvinyl chloride plastic up to 3 m length) transmit surprisingly well ultracold and very cold neutrons. When covered with a thin layer of a liquid fluorine polymer a transmission probability of up to 85% per meter has been measured. Those flexible tubes may be used to make portable sources of ultracold and thermal neutrons. They have been successfully used in the calibration of thermal neutron counters surrounding the storage volume of a recent neutron lifetime experiment. Preliminary results on this calibration and the neutron lifetime are presented. * Russian patent

Speaker: Dr Peter Geltenbort (Institut Laue-Langevin)

lunch

Session Mo - 3

14 Spacetime-Symmetry Violations: Motivations, Phenomenology, and Tests

An important open question in fundamental physics concerns the nature of spacetime at distance scales associated with the Planck length. The widespread belief that probing such distances necessitates Planck-energy particles has impeded phenomenological and experimental research in this context. However, it has been realized that various theoretical approaches to underlying physics can accommodate Planck-scale violations of spacetime symmetries. This talk surveys the motivations for spacetime-symmetry research, the SME test framework, and experimental efforts in this field.

Speaker: Ralf Lehnert (UNAM)

15 Experimental search for Violation of Lorentz Symmetry

Violation of Lorentz symmetry arises in many extensions of the Standard Model aiming to include quantum gravity. Violation of CPT symmetry also necessarily leads to breaking of Lorentz symmetry, allowing CPT tests without the use of anti-particles. Spin coupling to a preferred frame naturally arises in many such models. We use a K-$^3$He co-magnetometer to constrain neutron spin coupling to a Lorentz and CPT violating background field, $|b_n|<3.7 10^{-33}$ GeV, improving previous limit by a factor of 30. I will also discuss future prospects for improving these limits by using $^21$Ne atoms and placing the experiment on the South Pole to eliminate the systematic effect due to Earth's rotation.

Speaker: Michael Romalis (Princeton University)

16 Probing Lorentz-invariance in 3He/129Xe clock-comparison experiments

Accurate frequency measurements currently give the strongest bounds on the validity of fundamental theories. We present new results from a 3He/129Xe clock-comparison experiment, where the free precession of the nuclear spins is used to probe Einsteins principle of relativity. In particular, the sidereal variation of the 3He/129Xe frequency induced by Lorentz-violating couplings is measured, from which new upper limits on leading order Lorentz-violation of the bound neutron could be derived. The extreme sensitivity of this "spin-clock" is based on the fact that the oscillator is decoupled from any environmental influences.

Speaker: Prof. Werner Heil (Institute of Physics)

17 A Torsion Pendulum Based Axion Search

Despite two decades of experimental effort, the elusive axion has yet to be found. Nevertheless, for possible axion masses between 10~$\mu$eV and 10~meV, it remains a well motivated solution to the strong CP problem, and a promising dark matter candidate. Current searches use the axion-two-photon coupling to probe for axions that could be generated in the sun, remnants from the big-bang or created in the laboratory. Using techniques inspired by torsion pendulum based tests of gravity, we have constructed a new torsion pendulum experiment that looks for a macroscopic parity and time violating force mediated by virtual axions. For an axion mass of 1~meV, we have improved the limit on this force by ten orders of magnitude. In addition, we have demonstrated that one can operate a torsion pendulum in a strong magnetic field, and thus, have opened another path to look for very heavy axions.

Speaker: Dr Seth Hoedl (University of Washington)

Slides Hoedl_PSI_2010_nomovie.pdf

Coffee Break

Session Mo - 4

18 An Ultra-cold Neutron User Facility at Los Alamos National Lab

An ultra-cold neutron source has been constructed and is now operating at Los Alamos National Lab. This source, which is based on a solid deuterium converter driven by pulsed spallation-produced neutrons, provides UCN densities of 30 UCN/cc with negligible source-related backgrounds. The source is able to simultaneously provide UCNs to two experiment locations; the first is now occupied the by the UCNA experiment, but the second is available to user experiments. Our plans for continuing the operation of the source as a user facility, and the first planned experiments for both the UCNA apparatus and the second experiment station, will be described.

Speaker: Alexander Saunders (Los Alamos National Lab)

19 Final Performance of the Pulsed Superthermal UCN Sources at the TRIGA Mainz

Research in fundamental physics with the free neutron is one of the key tools for testing the Standard Model at low energies. Significant improvements of the experimental performance using ultracold neutrons (UCN) require reduction of both systematic and statistical errors. The development of new UCN sources based on the superthermal concept is therefore an important step for the success of future fundamental physics with ultracold neutrons. Besides the construction of new huge UCN sources at several big research centers around the world, which are mainly based on the use of either solid deuterium or superfluid helium as UCN converter, there exists also the idea of competitive UCN sources using pulsed reactors of the TRIGA type. To demonstrate the feasibility of a UCN source at these reactors, a superthermal UCN source based on solid deuterium was built at the tangential beamport C of the reactor TRIGA Mainz. Based on the experience obtained during three years of succesfull operation and optimisation, a second upgraded source was built for the radial beamport D. This new source schould increase the actually available UCN densities of 4 UCN/cm³ by minium one order of magnitude.

Speaker: Dr Thorsten Lauer (University of Mainz)

Slides PSI2010_Lauer.pptx

20 Status of the Ultracold Neutron Source at PSI

Commissioning of the new ultracold neutron (UCN) source at the Paul Scherrer Institut (PSI) has started. The design goal of this new generation high-intensity UCN source is to exceed the currently available ultracold neutron densities by a factor of ~100, thus making it very valuable for fundamental physics research like the search for a neutron electric dipole moment. The source will deliver these densities into two experimental areas. The key features are a very intense (Ip > 2.2 mA) pulsed proton beam with a low duty cycle (1%), a lead/Zircaloy spallation target, a 3.6 m3 heavy water moderator and a 30 liter solid Deuterium (sD2) converter system. Spallation neutrons are thermalized in the heavy water, further cooled and partially downscattered into the ultracold energy regime (E < 300 neV) in the sD2 crystal. Installation of most of the components has been completed. Commissioning of the facility will be finished within this year including the first cool-down and UCN production. An overview of the design of the source is reported as well as the current status of assembly and commissioning.

Speaker: Dr Bertrand Blau (PSI)

21 The Ultra-Cold Neutron Source at the FRM-II

A new strong source for the production of ultra-cold neutrons (UCN) is currently built up at the FRM-II. It will be installed at the horizontal beam tube SR-6, with a solid hydrogen pre-moderator and a solid deuterium UCN-converter located approx. 60 cm away from the reactor fuel element. UCN are produced inside the solid deuterium via the superthermal principle of conversion of the pre-cooled neutrons coming from the solid hydrogen. The UCN will be extracted from the converter and guided through the biological shield to several experiments located inside the experimental halls of the FRM-II. These experiments are investigating fundamental properties of the free neutron, such as its lifetime, a possible electric dipole moment or the quantum mechanical interaction of neutrons with the earth’s magnetic field. The expected UCN densities in the experiments will be 2-3 orders of magnitude higher than the densities reached at the currently strongest UCN-source located at the ILL. This talk will give an overview of the setup of the UCN source at the FRM-II and of the connected experiments. The current status of the project and future developments will be presented.

Speaker: Dr Andreas Frei (Physik Department E18 - Technische Universität München)

22 Production of UCN at J-PARC

The application of the pulsed proton beam from the Japan Proton Accelerator Research Complex (J-PARC) to produce ultracold neutrons is proposed for the measurement of the electric dipole moment of neutrons. An active optics synchronized with the UCN time-of-flight is proposed to suppress the decrease of the spatial UCN density on transporting the instantaneousely dense UCNs into a remote storage volume. We report the study of the active transport optics and the design of the UCN system.

Speaker: Prof. Hirohiko Shimizu (KEK)

23 Preparation of facilities for fundamental research with ultracold neutrons at PNPI

The WWR-M reactor of PNPI offers a unique opportunity to prepare a source for ultracold neutrons (UCN) in an environment of high neutron flux (about 3x10^12 n/cm2/s) but still acceptable radiation heat release (about 4x10^-3 W/g). It can be realized within the thermal column situated close to the reactor core. With its large diameter of 1 m, this channel allows to install a 15-cm-thick bismuth shielding, a graphite moderator at room temperature, liquid deuterium premoderator and a superfluid helium converter (35 dm3). At a temperature of 1.2 K it is possible to remove the heat release power of about 20 W. Using 4pi flux of cold neutrons within the reactor column can bring more than a factor 100 of cold neutron flux incident on the superfluid helium with respect to the present cold neutron beam conditions at the ILL reactor. The storage lifetime for UCN in superfluid He at 1.2 K is about 30 s, which is sufficient when feeding experiments requiring a similar filling time. The calculated density of UCN with energy between 50 and 230 neV in an experimental volume of 40 l is about 10^4 n/cm3. Technical solutions for realization of the project are discussed.

Speaker: Mr Arcady Zakharov (Petersburg Nuclear Physics Institute)

Evening Concert

24 Konzert D-Dur für 4 Trompeten, Pauke und Orgel

25 Welcome

26 Fuge g-moll für 4 Trompeten

27 Passacaglia e-Moll op. 156 Nr. 11

28 Fanfare for St. Edmundsbury, 1959

29 Introduction to "Quadrophonia"

30 Quadrophonia für 4 Trompeten

31 Fuge f-Moll (1839) für Orgel

32 "Denn er hat...", Aus dem „Elias“, für 4 Trompeten, Pauke und Orgel

33 Passacaglia in D für Orgel

34 Kanon für 4 Trompeten und Orgel

35 Verabschiedung & Dank

36 Prélude aus „Te Deum Laudamus“ für 4 Trompeten, Pauke und Orgel

Tuesday 12 October

Session Tu - 1

37 Hadronic physics and precision experiments

I will discuss the role of hadronic physics in precision experiments with the help of a few examples.

Speaker: Gilberto Colangelo (University of Bern)

38 In Search of Mu->eGamma – The MEG Experiment Status & Latest Results

The search for “New Physics” is not restricted to the high-energy frontier of TeV-scale accelerators. The MEG experiment at PSI, is a lepton-flavour violating decay search, aiming at O(10-13) sensitivity for the decay mu  e + gamma. Using one of the most intense surface muon beams, together with the world’s largest liquid xenon photon detector of 900 litres and a gradient-field superconducting positron spectrometer, the decay of a muon to a photon and positron can be distinguished from the normal Michel decay and the prompt background process of radiative muon decay. To resolve the dominant background process of accidental overlapping events, a detector with excellent spatial, temporal and energy resolution is required. The current status of the experiment as well as the latest results will be presented.

Speaker: Peter-Raymond Kettle (Paul Scherrer Institute PSI)

Slides Kettle-MEG.pdf

39 Results and opportunities in pion and muon decay

This talk will review the motivation, present experimental status, and remaining opportunities in the precise determination of the parameters of rare pion and muon decays. A great deal of effort, much of it at PSI, has been devoted in recent years to such measurements, leading to considerable improvements in precision, and in theoretical bounds. All of the measurements discussed explore various possible extensions of the standard model through tests of lepton universality, of the CVC hypothesis and Cabibbo universality, or of the V-A nature of the weak interaction. Even after the experiments of the current generation are completed, there will remain considerable room for improvement, typically an order of magnitude in precision, to match the theoretical accuracy. This leaves open significant opportunities for the future of the field.

Speaker: Dinko Pocanic (University)

Slides foils.pdf

Coffee Break

Session Tu - 2

40 Symmetry violations in few-body reactions: old and new approaches

The study of parity violating (PV) and time reversal invariance violating (TRIV) effects in low energy physics are very important problems for understanding main features of the Standard model and for a search for new physics. During the past 50 years many calculations of different PV and TRIV effects in nuclear physics have been done. However, in the last few years it became clear that the traditional methods for the calculation of PV effects have difficulties in describing the available set of experimental data. A comprehensive study of few-body systems could clarify the origin of these theoretical difficulties since for these systems all strong interaction effects can treated with much better accuracy than for many-body nuclei. As an attempt for this study, the overview of methods of calculations of PV and TRIV effects in few-body neutron induced reactions is presented with the analysis of values of calculated parameters and their accuracy.

Speaker: Prof. Vladimir Gudkov (University of South Carolina)

Slides PSI2010.pdf

41 Beta Asymmetry Measurement in Neutron Decay

The neutron decay spectrometer PERKEO III was installed at the Institut Laue-Langevin. An intense pulsed cold neutron beam was used to minimize systematic effects in a measurement of the beta asymmetry. We present results from the latest run.

Speaker: Dr Bastian Märkisch (Physikalisches Institut, Universität Heidelberg)

42 R-correlation in neutron decay: search for scalar and tensor couplings in weak interactions

The Standard Model (SM) predictions of T-violation for weak decays of systems built up of u and d quarks are by 7 to 10 orders of magnitude lower than the experimental accuracies attainable at present. It is a general presumption that time reversal phenomena are caused by a tiny admixture of exotic interaction terms. Therefore, weak decays provide a favorable testing ground in a search for such feeble forces. Physics with very slow, polarized neutrons has a great potential in this respect. Our experiment seeks for small deviations from the SM in two observables that have never before been addressed experimentally in free neutron decay. The first of these, the R-correlation coefficient, is proportional to the electron polarization component perpendicular to the plane spanned by the spin of the decaying neutron and the electron momentum. Its non-zero value (corrected for the electromagnetic effects) would signal a violation of time reversal symmetry and thus an existence of physics beyond the Standard Model. The second observable, the N-correlation coefficient, is given by the transverse electron polarization component within the above mentioned plane. Within the SM its value is significantly different from zero and it scales with the decay asymmetry parameter A. The measurement of N, both, probes the SM and serves as an important systematic check of the experimental apparatus with respect to the R-correlation measurement. The N- and R-correlation coefficients are sensitive to real and imaginary parts of the same linear combination of the scalar and tensor interaction coupling constants, respectively. Experimental determination of the N and R coefficients will help to further constrain possible contributions of these exotic couplings. The experiment has been carried out on the polarized cold neutron beam facility FUNSPIN of the SINQ spallation source at the Paul Scherrer Institute, Villigen, Switzerland. The transverse polarization of electrons from the neutron decay was analyzed in the Mott scattering from lead nuclei. Data taking has been completed and the analysis is in progress. The newest results will be presented. A possible future experiment leading to the accuracy improved by at least an order of magnitude will be discussed.

Speaker: Prof. Kazimierz Bodek (Uniwersytet Jagiellonski, Instytut Fizyki, Krakow, Poland)

Slides PSI2010_Bodek.ppt

43 aSPECT: Measurement of the Proton Spectrum in Neutron Decay

The purpose of the retardation spectrometer aSPECT is to determine the antineutrino electron angular correlation coefficient 'a' with high precision, by measuring the integral proton spectrum in free neutron decay. A precise measurement of 'a' allows high precision tests of the Standard Model and physics beyond, i.e. the unitarity of the quark mixing CKM matrix, right handed currents, or scalar and tensor interactions. Latest measurements with aSPECT were performed during April/ May 2008 at the Institut Laue-Langevin in Grenoble, France. The physical motivation and the design and optimization of the spectrometer as well as the status of the data analysis will be presented in this talk. I will close my speech with a discussion of possible further measurements.

Speaker: Ms Gertrud Konrad (University of Mainz, Mainz, Germany)

Slides aSPECT_PSI2010_GK_WEB.pdf

44 UCNA: A High Precision Measurement of the Axial Form Factor of the Nucleon using Ultracold Neutrons

UCNA: A High Precision Measurement of the Axial Form Factor of the Nucleon using Ultracold Neutrons The UCNA experiment has produced a 1.4% measurement of the beta-asymmetry in neutron decay using polarized ultracold neutrons, yielding a high precision value for the axial coupling constant, gA/gV, for the charged weak interaction of the nucleon. UCNA is situated at the spallation solid deuterium UCN source at Los Alamos National Lab and is the first experiment to utilize ultracold neutrons for an angular correlation measurement in neutron decay. Ultracold neutrons offer significant advantages for the polarization and neutron-generated background systematic uncertainties in the measurement. We report on the results of our 2008-2009 data acquisition run, the current status of the experiment, and future plans for other experiments using the UCNA spectrometer.

Speaker: Prof. Albert Young (North Carolina State University and the Triangle Universities Nuclear Laboratory)

45 Tracing Remnants of the Baryon Vector Current Anomaly in Neutron Radiative $\beta$-Decay

We show that a triple-product correlation in the neutron radiative $\beta$-decay rate, characterized by the kinematical variable ${\mathbf l}_p\cdot({\mathbf l}_e\times{\mathbf k})$, isolates the pseudo-Chern-Simons term found by Harvey, Hill, and Hill as a consequence of the baryon vector current anomaly and SU(2)$\times$U(1) gauge invariance at low energies. We consider the bound which emerges on the strength of its neutral current analogue from MiniBooNE data and compute the size of the expected asymmetry in $n\to p e^- \bar\nu_e \gamma$.

Speaker: Prof. Susan Gardner (University of Kentucky)

Slides trace_psi10.pdf

lunch

Session Tu - 3

46 Precision measurement of the positive muon lifetime by the MuLan collaboration

The Fermi constant $G_\mathrm{F}$ governs the rates of all weak interaction processes and, along with the fine structure constant $\alpha$ and the $Z$-boson mass $M_Z$, it is one of the principal input parameters to the Standard Model. Owing to the purely leptonic nature of the muon decay process, $G_\mathrm{F}$ is extracted most precisely from measurements of the muon lifetime $\tau_\mu$. In 1999, the publication of missing radiative corrections effectively eliminated the largest, purely theoretical uncertainty in extracting $G_\mathrm{F}$ from $\tau_\mu$. At present, the precision in $G_\mathrm{F}$ is limited by experimental uncertainty in $\tau_\mu$. We report a measurement of the positive muon lifetime to a precision of one part-per-million, a better than twenty-fold improvement over the previoius generation of experiments. The new result will improve precision in $G_F$ to better than 0.8 parts-per-million. The MuLan experiment was conducted at the Paul Scherrer Institute in Villigen, Switzerland, using a pulsed surface muon beam, in-vacuum muon-stopping targets, and a large acceptance, finely segmented scintillator array. We will describe our measurement method and report our final result.

Speaker: Prof. David Hertzog (University of Washington)

Slides PSI-MuLan-final.pdf PSI-MuLan-final.ppt

47 Muon capture on light nuclei

The current theoretical and experimental status for muon captures on light nuclei will be reviewed. In particular, a new theoretical study of muon captures on deuteron and 3He will be presented, in which realistic potentials and consistent weak currents are used, and it will be shown that it is possible to reduce the model dependence relative to the adopted interactions and currents at the 1% level. The implications of this for future possible experimental programs will also be discussed.

Speaker: Dr Laura Elisa Marcucci (Department of Physics, University of Pisa)

Slides marcucci_public.pdf

Coffee Break

Session Tu - 4

48 Muon capture at PSI

The muon capture experiment MuCap uses a negative muon beam stopped in a time projection chamber as an active target filled with ultra-pure hydrogen gas. The elementary capture process mu- +p-> n+nu offers a rare (0.15%) but additional disappearance channel. The measured difference of the positive and negative muon's lifetime determines the rate of the capture process to a final precision of 1%. This can be used to derive an improved value of the proton's pseudoscalar form factor gP to 7% precision. A first result gP = 7.3 +- 1.1 has been published [1]. This is a first precise, unambiguous determination of gP and an important test of QCD symmetries. The analysis of the full data set with a 2-3 times better precision will be finalized soon. Our new experiment, MuSun [2] will measure the doublet capture rate of the mu- +d -> n+n+nu providing a benchmark of the understanding of weak processes in the two nucleon-system. It was shown, that other weak reactions involving the two nucleon system (pp -> d e+ nu or neutrino-deuteron reactions) are related to the same low-energy constant, characterizing the two nucleon system at short distances. This constant is not well constrained and therefore the MuSun experiment comes closest to calibrating these basic astrophysical reactions under terrestrial conditions. The experiment will use a newly developed time projection chamber at 30 K which is currently designed. A commissioning test with the full cryogenic setup succeeded in spring 2010 and a first physics run is scheduled for October 2010. [1] Phys. Rev. Lett. 99, 032002 (2007) [2] http://www.npl.uiuc.edu/exp/musun/documents/prop07.pdf

Speaker: Dr Peter Winter (University of Washington)

Slides PSI2010_Winter_Online.pdf PSI2010_Winter_Online.ppt

49 Muon lifetime measurement with the FAST detector at PSI

The Fibre Active Scintillator Target (FAST) experiment at the Paul Scherrer Institute is designed to measure the $\mu^+$ lifetime to 4 ps precision and thereby to determine the Fermi coupling constant, $G_F$, to 1 ppm. In FAST, a $\pi^+$ beam is stopped inside a highly granular target which images the entire $\pi^+\rightarrow \mu^+\rightarrow e^+$ decay chain. To achieve the high statistics required, the detector has a modular structure which allows simultaneous mesurements of several decay chains. The concept of the FAST detector provides strong intrinsic suppression of potential systematic effects and allows operation at high beam rates. In 2008 and 2009, FAST collected a total statistics of $4.2\times10^{11}$ identified $\mu^+$ decays, allowing a statistical precision of 1.2 ppm on $G_F$. The analysis of these data will be presented.

Speaker: Dr Eusebio Sanchez (CIEMAT - Madrid)

Slides fast_psi2010.pdf

50 MuSIC: A new DC muon beamline at RCNP

A new DC muon source is under construction at Research Center of Nuclear Physics (RCNP), Osaka University. The ring cyclotron of RCNP can provide 400W 400MeV proton beam. Using this proton beam, the MuSIC produces a high intense muon beam. The target muon intensity in 10^8 muons/second, which is achieved by a pion capture with great efficiency to collect pions and muons using a solenoidal magnetic field. A pion production target system is located in a 5 Tesla solenoidal magnetic field generated by a super-conducting solenoid magnet. The proton beam hits the target, and backward pions and muons are captured by the field. Then they are transported by a curved solenoid beam line to experimental apparatus.The construction has been started at 2010, and would be finished in 5 years. We plan to carry out not only an experiment to search the lepton flavor violating process but also other experiments for muon science and their applications using the intense muon beam.

Speaker: Dr Akira Sato (Osaka University)

Slides 101012_music_sato.pdf

Poster Session

51 A cryogenically-cooled source of YbF molecules for measuring the electron's electric dipole moment

Certain polar molecules can be used to measure the electron's electric dipole moment (edm) to high precision. In our electron edm measurement at Imperial College London, we currently use a beam of YbF molecules derived from a supersonic source. We are developing a new source of cold YbF molecules based on cryogenic buffer gas cooling. The molecules are created by laser ablation inside a cryogenically-cooled cell of helium gas. They are cooled to the helium temperature and then leave the cell through a hole to form an intense, slow-moving, cold beam. We present our measurements of the intensity, speed and temperature of this new YbF beam, and discuss how we will use it to the benefit of a new edm measurement.

Speaker: Dr Michael Tarbutt (Imperial College London)

52 A polarized UCN physics beam position at the FRM-2

We present a concept for a polarized UCN physics beam position at the FRM-2. The use of a superconducting magnet with an adiabatic fast passage (AFP) spin flipper at the field maximum allows free tuning of the UCN energy spectrum. Based on work by Alefeld et al.[1] and Weinfurter et al.[2], we use the level splitting in a magnetic field of |2mB| and add a spin flip in the center of the magnetic field which doubles the level splitting to |4mB|. Therefore, the energies of the spin states will be significantly separated after leaving the magnet. We intend to use neutrons with energies above the Fermi potential of typical storage materials, which have good transport properties through UCN guides and higher available flux. By shifting the energy spectrum, a significant gain in polarized storable UCN density in the experiment should be feasible. Modifying the magnetic field and the resonant RF field further allows adjusting the UCN spectrum to different energies. The principle setup of such a beam position and MC simulations will be presented. [1] B. Alefeld, G. Badurek and H. Rauch, Z. Phys . B41 (1981) 231 [2] H. Weinfurter, G. Badurek, H. Rauch and D. Schwahn, Z. Phys . B72 (1988) 195

Speaker: Dr Gerd Petzoldt (Center for Particle Physics with Neutrons - Technische Universität München)

53 A study of recoil terms for beta transitions in mirror and triplet nuclei.

In the Standard Model the Hamiltonian of the weak interaction consists of a vector and a axial-vector part, but in the most general Lorentz-invariant form of this Hamiltonian a tensor and a scalar part are in principle possible. In beta decay these are searched for by precise determinations of the corrected Ft values of superallowed Fermi transitions and precision measurements of correlations between the spins and momenta of the particles involved. In recent years the precision of such measurements has improved significantly and is now at the level of 1% or better with even better precisions being possible in the near future. For measurements at the precision of 1% or better, higher order corrections can mimic the effects of physics beyond the Standard Model and should therefore be included in the vector and axial-vector part of the Hamiltonian. The most important of these are the so-called recoil terms related to induced weak currents, which occur because the decaying quark couples to the weak field as a bound particle in the nucleon, and not as a free particle. The formalism of these recoil terms is written down by B. R. Holstein [HOL1974] in terms of form factors. The most important ones are the weak magnetism b and the induced tensor d. These terms modify the correlation coefficients in the order of several permil up to about several percent in extreme cases. Here we present a study of the recoil terms and their effects in correlation coefficients for a number of beta transitions between mirror nuclei and between triplet nuclei. The weak magnetism form factor is experimentally derived using the CVC hypothesis [CAL1976]. The matrix elements leading to the form factors relevant for the recoil terms are calculated in the nuclear shell model using the impulse approximation and, if possible, compared with experimental values. [Hol1974] B.R. Holstein, Review of Modern Physics 46 (1974) 789 [Cal1976] F.P. Calaprice and B.R. Holstein, Nuclear Physics A 273 (1976) 301

Speaker: Ms Veronique De Leebeeck (IKS, Katholieke Universiteit Leuven)

54 An ultracold neutron source at the NC State University PULSTAR reactor

Speaker: Albert Young

55 Cesium magnetometers for field and gradient control in the neutron EDM search.

Laser optically-pumped Cs magnetometers (OPMs) have a sensitivity which rivals that of the SQUID, without requiring cryogenic infrastructure. Advances in size reduction, digital signal processing, and single-to-multi laser beam splitting methods have made it possible to assemble arrays of Cs magnetometers. We have successfully operated a 25 sensor array for biomagnetic measurements [1], and are adapting the technology to the demanding task of spatial and temporal field control for the PSI nEDM experiment. In this poster we present the OPM technology, and evaluate and show solutions to some of the nEDM-specific challenges (vacuum and high voltage compatibility). We present first results on using the OPMs to detect the free precession of 3He nuclear magnetization. [1] G. Bison, et al., Appl. Phys. Lett. 95, 173701 (2009).

Speakers: Prof. Antoine Weis (Department of Physics, University of Fribourg), Dr Malgorzata Kasprzak (Department of Physics, University of Fribourg), Dr Paul Knowles (Department of Physics, University of Fribourg)

56 Design and performance of new electronic system of Cs-magnetometers array for the planned UCN EDM experiment at PSI

The precise measurement and control of magnetic fields and magnetic field fluctuations is an important step for experiments searching for a permanent electric dipole moment (EDM) of the neutron, and is one of the main factors limiting the accuracy. In a project approved by Paul Scherrer Institute (PSI), a neutron EDM spectrometer is proposed. For this experiment, together with Fribourg university, we have build arrays of Cs detectors and FPGA-DSP based electronics, with phase-locked schema to get stable operation of the Cs sensors. Electronic module includes 16 channels, with independent phase locked feedback and digital frequency syntheses. Internal DSP helps to find a resonance frequency in quite big range of the magnetic field and has a enough speed to follow the changes of the magnetic field. DSP includes also different subroutines for data reprocessing, which could be updated trough internet communication. First noise measurements shows quite promising results(below 300fT RMS) and electronic module is specifically good to find and lock narrow resonance lines.

Speaker: Dr alexander mtchedlishvili (Dr)

57 Design of a novel pulsed spin resonator for the beta-decay experiment PERC

The PERC (Proton Electron Radiation Channel) project searches for new physics beyond the Standard Model of particle physics via the beta-decay of free neutrons. The demand of precisely defined initial parameters for the neutron beam, i.e. wavelength, pulse width and degree of polarisation is achieved by using both a velocity selector and a neutron chopper in the “standard” set-up [1]. The use of a novel pulsed neutron magnetic spin resonator as a replacement for these two components will lead to a higher count rate and will give rise to a unique flexibility in triggering the standard machine parameters by purely electronic means. It is well known that the passage of polarised neutrons through a spatially alternating transverse magnetic field is leading to individual frequencies depending on the neutron velocity and the period of the alternating field. If this frequency equals the Larmor frequency, determined by the static guide field in the rest frame of the neutrons, a resonant spin flip will take place. This effect is used to monochromatise a polarised beam [2, 3]. We propose a novel design of such a resonator consisting of a sequence of separate modules, providing high homogeneity of the transversal field oscillations and fulfilling the specifications for fast electronic switching to allow a rapid chopping of the beam [4]. Both the selected wavelength and the respective wavelength resolution of this device can be changed in an instant as well as the time structure of the neutron pulse can be changed. In order to find the optimal resonator configuration we present a detailed analysis of various possible arrangements. Although motivated by the requirements of the PERC project this development could readily find applications in various fundamental precision experiments with cold neutrons. References 1. Dubbers, D., et al., A clean, bright, and versatile source of neutron decay products. Nuclear Instruments and Methods in Physics Research A, 2008. 596(2): p. 238-247. 2. Agamalyan, M.M., G.M. Drabkin, and V.I. Sbitnev, Spatial spin resonance of polarized neutrons. A tunable slow neutron filter. Physics Reports, 1988. 168(5): p. 265-303. 3. Drabkin, G.M., V.A. Trunov, and V.B. Runov, Static magnetic field analysis of a polarized neutron spectrum. Sov. Phys. JETP, 1968. 27: p. 194. 4. Badurek, G. and E. Jericha, Upon the versatility of spatial neutron magnetic spin resonance. Physica B, 2003. 335: p. 215-218.

Speaker: Mr Christoph Goesselsberger (Vienna University of Technology, Atominstitut)

Poster PSI2010_Gösselsberger.pdf

58 Development of a backscatter-free beta spectrometer for determination of weak magnetism recoil terms in allowed transitions

Nuclear beta decay experiments for precision studies of the weak interactions are searching for new types of interactions, such as scalar and tensor components of the weak currents. The beta-neutrino correlation, the beta-asymmetry parameter, and the ft-values of the superallowed pure Fermi transitions have high sensitivity for scalar and/or tensor contributions [Sev2006]. A significant progress in the accuracy for each of these variables has been reached in the last decades. For example, for different nuclei the beta-neutrino correlation is determined with a precision of 0.5% to 1.1% [Gor2005] and the beta-asymmetry parameter with an accuracy of 1.4% [Wau2009a]. Various groups are currently improving their experimental setups and methods while new experiments are in preparation, which allows to expect that precision levels below 0.5% are to be reached in the near future. At such precision, higher order effects in the vector and axial-vector currents should be taken into account [Sev2006]. In the Standard Model the most significant higher order corrections are related to the form factors - b, the weak magnetism, and - d, the induced tensor, both originating from the hadronic structure of the nucleons. The contributions of these "recoil" terms, scaling with E/M, cause small changes (typically of the order of 0.1% to 0.5%) to the values of the correlation coefficients, which may mask the effects of new physics. Our goal is to investigate in detail the recoil effects both theoretically and experimentally. Recent advances of computational techniques allow to calculate matrix elements which determine the recoil terms based on the theoretical formalism developed by B. R. Holstein [Hol1974]. For the experimental determination of the recoil terms a new compact beta spectrometer is being developed. Its main purpose is to measure shapes of beta spectra with corrections for the energy dependent backscattering. The shape of the beta spectrum can be used to determine the weak magnetism term, b [Cal1976]. In addition, backscattering data from the measurements will be used to improve GEANT4 based simulations, which are used for reduction of the systematical errors in beta asymmetry measurements [Wau2009b]. The final version of the spectrometer is planned to suit as a portable backscatter-free detector for future use in beta decay experiments. The spectrometer consists of two main parts: a solid state detector for energy measurements and a multi-wire drift chamber [Loj2009] for detection and suppression of the backscattered electrons. This spectrometer design allows achieving up to 100 times higher efficiencies compared to the magnetic spectrometers used in the past. [Sev2006] N. Severijns, M. Beck, and O. Naviliat-Cuncic, Review of Modern Physics 78 (2006) 991 [Gor2005] A. Gorelov et al., Physical Review Letters 94 (2005) 142501 [Wau2009a] F. Wauters et al., Physical Review C 80 (2009) 062501 [Hol1974] B.R. Holstein, Review of Modern Physics 46 (1974) 789 [Wau2009b] F. Wauters et al., Nuclear Instruments and Methods A 609 (2009) 156 [Cal1976] F.P. Calaprice and B.R. Holstein, Nuclear Physics A 273 (1976) 301 [Loj2009] K. Łojek, K. Bodek, and M. Kuźniak, Nuclear Instruments and Methods A 611 (2009) 284

Speaker: Dr Emil Traykov (IKS, Katholieke Universiteit Leuven)

59 Development of fixed-field gradient magnet in time focusing system for ultracold neutron beam

It is proposed to construct ultra-cold neutron (UCN) source and to perform an experimental search of neutron electric dipole moment (nEDM) at J-PARC in Japan. One of key technique in the proposal is time focusing of UCN beam with so-called "rebuncher"s. In the rebuncher, fast UCNs in a bunch are decelerated and slow ones are accelerated by using a rf spin flipper and a fixed-field-gradient magnet. As the results, a stretched-bunch-length due to time of flight difference in velocity during a transportation will be shortened at an nEDM measurement apparatus and the density of UCN at the apparatus will be increased. The magnet of the rebuncher has a unique feature. Here a development status of the magnet will be described.

Speaker: Dr Yasushi Arimoto (IMSS, KEK)

Poster 101012-psi-arimoto.pdf

60 Development of NMOR magnetometer for spin-maser EDM experiment

We have been investigating the frequency stability of the low-frequency nuclear spin maser with 129Xe aiming at EDM (permanent Electric Dipole Moment) experiment. One of the main sources of this frequency instability comes from the field fluctuation of the applied static field B0. The present stability 30 nG of the applied field B0=30 mG in a time scale of 10^4 s should be suppressed by use of a highly sensitive magnetometer. We are now preparing for operation of Rb magnetometer based on NMOR (Nonlinear Magneto Optical Rotation) in the spin maser experiment. Systematic measurement of the NMOR spectrum with several Rb cells coated with an antirelaxation agent or including buffer gas was performed. We also started to operate the NMOR magnetometer with a frequency modulated laser beam in order to be used at B0=30 mG. We will present the present status of the above development and the prospect for the EDM experiment.

Speaker: Dr Akihiro Yoshimi (RIKEN)

61 Free Fall Experiment with UCN

We performed a gravity quantum experiment for the test of weak equivalence principle for free neutron. The gain in kinetic energy of free falling neutrons was is compensated by a quantum of energy \hbar \Omega, due to the phase modulation of the neutron wave. As phase modulator a grating was used moving perpendicular with respect to the direction of the neutron wave propagation. The neutron interference filters, neutron analogs of the Fabry-Perot interferometers were used both as for the primary monochromatization and for the neutron energy analyzing after the falling. By the comparison of the quantities mgh and \hbar \Omega the weak equivalence principle was tested with accuracy 0.2%. At nearest future we plan to perform the next experiment with a modified procedure using a new spectrometer, which is under construction now. As before, neutron interference filters will be used as a spectrometric device and the controlled variation of the neutron energy will be realized by diffraction by a moving grating. But the energy of the neutron will be measured by a peculiar time-of-flight method. For this purpose the neutron flux will be modulated by a chopper and the detector will measure the corresponding oscillation of the count rate. The count rate oscillation phase \Phi=2*Pi*F*t, where F is the frequency of the chopper, is proportional to the time of flight t. Due to the high neutron monochromatization relatively large modulation frequencies can be used. An analysis shows that using the same UCN source it is possible to increase the accuracy of the experiment approximately by one order of magnitude. First test of new spectrometer is scheduled for the end of 2010.

Speaker: Mr German Kulin (FLNP, JINR, Dubna, Russia)

62 GEANT4 simulations used in the search for tensor type weak currents

The precise measurement of the beta-asymmetry parameter is a sensitive tool to search for tensor type currents in the weak interaction. Our group uses the technique of Low Temperature Nuclear Orientation and several particle detectors to observe the emission anisotropies. The precision we aim for requires a thorough study of all the effects that modify the observed emission pattern of the beta-radiation. We developed a GEANT4 based Monte Carlo code which incorporates the experimental setup, allowing good control over systematic effects. Using these simulations we determined the most precise value of the beta-asymmetry parameter to date. In this poster the validation of the GEANT4 code is presented. Simulated and experimental spectra of Si PIN diodes and planar HPGe particle detectors are compared to verify the accuracy of the simulations. Comparisons of GEANT4 physics models are also shown.

Speaker: Mr Gergelj Soti (Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium)

Poster psi_soti.pdf

63 INSTRUMENTATION AT THE PAUL SCHERRER INSTITUT’S ULTRA-COLD NEUTRON SOURCE

The ultra-cold neutron (UCN) source at the Paul Scherrer Intstitute uses the full 1.3 MW proton beam on a spallation targetin a heavy water moderation system including a deuterium crystal at a temperature of about 6 K as cold source and converter. The produced UCN will be confined in a storage volume and can be distributed to the experiments via 7-10 m long UCN guides. We here report on the monitoring and surveillance systems of the source, with emphasis on sensors in the high radiation and cryogenic environment. A UCN detection system was developed to monitor the produced UCN density inside the intermediate storage volume and after ~3.5m of UCN guide while only negligibly influencing UCN density itself. The detector system was designed and tested to withstand 20 years of source operation which corresponds to a fluence of 1018 n/cm2 for the scintillator and the first centimeters of the light guides. Energy resolution will be obtained by using several detectors with coatings of different material optical potential.

Speaker: Mr Leonard goeltl (Paul Scherrer Institut)

64 Lamb shift in muonic helium

for the CREMA collaboration In order to shed some light on the observed proton radius discrepancy we plan to measure several 2S-2P transitions in muonic helium ions (mu4He+ a nd mu3He+). The aim of this measurement is three-fold: first it will verify the correctness of the muHe+ Lamb shifts prediction (using the nuclear radii from electron scattering). This will serve as validation of muonic bound-state QED theory. Second, if the muHe+ theory is assumed to be correct, the alpha-particle and the helion rms charge radii can be determined. These radii are relevant parameters for the verification of few-nucleon theories and potentials. Third, combined with an ongoing experiment at MPQ aiming to measure the 1S-2S transition frequency in He+, these measurements will open the way to test interesting bound-state QED terms in He+. The B60 term for example could be checked to 5 relative accuracy i.e., five times better than in hydrogen. The contribution of the finite size effect to the Lamb shift in muHe+ is as high as 20%. Therefore a measurement of the transition frequencies with a precision of 50 ppm (corresponding to 1/20 of the natural linewidth which is 320 GHz) will provide rms nuclear charge radii with ur=3x104 (equivalent to 0.0005 fm). This is limited by the nuclear polarizability contribution

Speaker: Aldo Antognini (ETH - Zurich)

65 Macroscopic quantum phenomenon appeared under neutron moving in magnetic channel

Today's strong permanent magnets offer unique possibilities to develop novel magnetic structures. Practically any imaginable magnetic field configuration can be realized with them. As an example the magnetic structure type of two dimensional potential well was be realized to study quantum effects in magnetic and magneto-gravitational traps. Macroscopic quantum effects under neutron moving in such magnetic channels were observed. Energy of observed levels is equal to 3 10-12 eV. Some aspects of the experimental results treatments are discussed.

Speaker: Dr Vladimir Ryabov (Petersburg Nuclear Physics Institute RAS)

66 Measuring the electron’s electric dipole moment using YbF: data acquisition and analysis

It is well known that the existence of an electron electric dipole moment (eEDM) would violate time reversal symmetry. The Standard Model predicts an eEDM less than $10^{-40}\mathrm{\,e\,cm}$, however many popular extensions predict values in the range $10^{-29}-10^{-27}\mathrm{\,e\,cm}$. Our experiment currently has the potential to measure eEDMs down to approximately $5\times10^{-28}\mathrm{\,e\,cm}$, making it a precise probe for T-violation and physics beyond the Standard Model. We measure the eEDM by performing a type of separated oscillating field interferometry on a pulsed beam of YbF. The molecules are prepared such that the molecular spin is oriented perpendicular to an applied strong ($10\mathrm{\,kV/cm}$) electric field. The spin is then allowed to precess about the electric field axis over a $0.5\mathrm{\,ms}$ interaction period. We measure this angle of rotation, which is directly proportional to the eEDM. In order to measure the eEDM precisely and without systematic error we use a complex switching technique wherein certain parameters, including the applied electric and magnetic fields, are reversed between individual molecular pulses. We report our current technique in more detail as well as the tests we perform to check for systematic effects.

Speaker: Mr Joe Smallman (CCM)

Poster PSI2010_Poster.pdf

67 Neutron Bound Beta- Decay- BOB

S.Paul[1], M.Berger[1], R.Emmerich[1], R.Engels[2], .Faestermann[1],P.Fierlinger[3], M. Gabriel[1], F.J.Hartmann[1], R.Hertenberger[4], A.Röhrmoser[5], J.Schön[1], W.Schott[1],U.Schubert[1], A.Trautner[1],T.Udem[6] 1 Physik-Department,TUM,85748 Garching,Germany 2 Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich, Germany 3Excellence Cluster Universe, TUM, 85748 Garching, Germany 4 Sektion Physik, LMU, 85748 Garching, Germany 5 FRM2, TUM, 85748 Garching, Germany 6 Max- Planck- Institut für Quantenphysik, 85748 Garching, Germany The bound neutron β- decay( BOB) into a hydrogen atom and an electron antineutrino is investigated. The hyperfine-state population of the monoenergetic hydrogen atoms( 326.3 eV) yields the neutrino left-handedness or a possible right- handed admixture and possible small scalar and tensor contributions to the weak force. At a thermal neutron source the background can be suppressed using neutron and γ- ray absorbing traps after a beampipe going through the moderator tank, as MCNP4 and GEANT4 simulations for the FRM2 SR6 tube have shown. Preexperiments to measure the BOB H(2s) atoms have been done or are being set up using ionizer and RF discharge proton sources, a Wien filter, Cs and Ar cells, a spin filter, electric counter and accelerating fields, a double focusing magnet and an efficient channeltron type Lyman- α photon detector.

Speaker: Dr Wolfgang Schott (Physik-Department der TUM E18, D-85748 Garching)

68 Precision Studies of Few-Nucleon System Dynamics

A basic step towards a full understanding of nuclear interaction is a proper modeling of all details of the few-nucleon system dynamics. Systems composed of three nucleons (3N) are the simplest non-trivial environment to explore details of the nucleon-nucleon (NN) potential models and to investigate limits of a just two-nucleon based description of the interaction dynamics. In particular, data obtained for the elastic and breakup channels of the nucleon-deuteron (N-d) reaction have proven to be especially well suited to study subtle effects of suppressed degrees of freedom, described by means of three-nucleon forces (3NF). Effects of 3NF, although small, are very important and have far-reaching consequences in various fields of physics. Precise experimental results have shown, however, that also further dynamical ingredients are indispensable to correctly describe the data. The theoretical calculations, based on rigorous solutions of the Faddeev equations with the physical input taken e.g. as realistic NN potentials combined with model 3NF, as the two- and three-nucleon interactions obtained with the explicit treatment of the Delta-isobar excitation or as forces derived within Chiral Perturbation Theory methods, have to take into account also, for a long-time neglected, effects induced by the long-range Coulomb interaction and influences of relativity. In the elastic N-d channel numerous evidences of the 3NF effects have been found in the cross section data at intermediate energies. The polarization observables lead to a more complicated picture, indicating certain imperfections in construction of 3NF models, especially in their spin part. Precise measurements of the breakup process are experimentally very demanding, but fortunately the recent activities has been able to meet the requirements of providing rich and precise data sets. The results at every energy comprise several hundreds data points for each vector and/or tensor analyzing power, and a few thousands for cross sections. Their comparisons with predictions using nuclear interactions generated in various ways provided important insight into details of the few-body system dynamics. Just the cross-section data from the first new generation experiment at KVI allowed to establish a clear evidence of importance of the 3N forces in the breakup process. Moreover, the results confirmed predictions of sizable Coulomb force influences in certain phase space regions of this reaction, confirmed later in a dedicated experiment researching specially selected phase space regions. The outcome from the analysis of polarization observables is not-so-unambiguous. Therefore further studies are planned at several laboratories, which will investigate also the next more complicated system of four nucleons, also with respect to charge symmetry violation aspects of the NN interaction.

Speaker: Prof. Stanislaw Kistryn (Jagiellonian University)

Poster poster_sk.pdf

69 Properties of light pseudoscalar mesons

In my talk I would like to focus on light unflavoured pseudoscalar mesons. Mainly I want to discuss the properties of pi0 and its decay modes. In fact the decay modes of pi0 were subjects of many experiments in the past (including e.g. SINDRUM col. at PSI), present (e.g. KTeV, or PrimEx at JLab) or future (NA62 at CERN). Experiments have reached (or plan to reach) a level of precision which makes it mandatory to reopen previous theoretical calculations to achieve appropriate order (NLO or NNLO). This can, on one hand, help us to verify and fix underlying structure of the low energy effective theory of QCD - ChPT (e.g. pion decay constant, low energy constants, power-counting,etc.). On the other hand it can set a framework for study a new physics beyond SM (e.g. KTeV's discrepancy with a theory for pi0->e+e-). The eta meson can be treated technically very similarly. However, due to its mass one can also study its hadronic decays. This can provide us with important information on isospin breaking effects and again test internal consistency of ChPT.

Speaker: Karol Kampf (Lund University)

70 Search for long-range forces of a neutron and atoms with a trap of ultracold neutrons

A method of using a gravitational UCN spectrometer to search for long-range forces between neutrons and atoms is proposed. The constraints on the strength of long range forces within the range of 10^-10 - 10^-4 cm were obtained from the experiments on measurements of the total cross section of interaction of UCN with atoms of the noble gases and the data on the coherent neutron scattering length of the nucleus. Further prospects of UCN method is discussed.

Speaker: Mr Oleg Zherebtsov (Petersburg Nuclear Physics Institute)

Poster O.Zherebtsov_PSI2010.pdf

71 Search for spin-dependent short range interaction of the bound neutron in 3He/129Xe clock comparison experiments

A very sensitive low-field magnetometer based on the detection of free spin precession of gaseous, nuclear polarized 3He or 129Xe samples with a SQUID as magnetic flux detector is used to search for short-range spin-dependent interactions. The magnetic field dependence ( Zeeman-term) can be eliminated using co-located 3He/129Xe spin samples and measuring the weighted difference of their respective spin precession frequencies, i.e. Df= f_He – γHe / γXe f_Xe . Thus, one gets sensitive to purely non-magnetic interactions. We looked for a change in Df when heavy masses positioned close to the cylindrical sample cell were moved away during the measurement cycle. A sensitivity of ~5 nHz was obtained within 20 hours. Resulting limitations on spin-dependent short-range interactions will be discussed.

Speaker: Dr Yury Sobolev (Institut fuer Physik, Johannes-Gutenberg Universitaet, Mainz)

72 Sitall UCN-Messung

Preliminary laboratory researches have shown, that a polycrystalline glass ceramic named Sitall could be a very suitable material for future UCN-storage experiments. This material provides high mechanical and temperature strength plus good electric isolation characteristics and an effective wall potential for UCN of V=125 neV. Our aim was to prove the UCN storage characteristics of a Sitall glass-ceramic bottle produced from SRIOMT (Moscow, Russia). The cylindrical storage bottle was installed at the UCN-source C of the reactor TRIGA Mainz. After different cleaning processes, such as backing out and RF-discharge with helium, a storage time of 160(2) s was measured in a one-day experiment. The main UCN-losses arise from absorption and upscattering at the surface of the Sitall.

Poster Poster-PSI-Duesing-092010.pdf

73 Some implications of Strong CP-violation: Vacuum Polarization and Vacuum Birefringence

Strong CP-violation implies that a vacuum permeated by electromagnetic fields develops an anomalous electric dipole moment, parallel to the external magnetic field. We compute such an induced dipole moment using chiral perturbation theory and we show that CP-odd effects grow very rapidly with temperature. We also compute the anomalous CP-odd vacuum birefringence and its effect on linearly polarized photons propagating inside a Fabry-Perot cavity.

Speaker: Mr Raffaele Millo (University of Trento)

74 Standard Model Tests with PERC

We address a number of questions which are at the forefront of particle physics, with main emphasis on the search for new physics beyond the Standard Model of particles physics, and in particular, on the question of unification of all forces shortly after the Big Bang. This grand unification is not part of the Standard Model, and new symmetry concepts are needed like left-right symmetry, fundamental fermion compositeness, new particles, leptoquarks, supersymmetry, and many more. We present a case study on a new type of cold neutron beam station PERC, for the investigation of various observables in free neutron's b-decay. With PERC, we will be able to obtain a beam of decay electrons and protons under well-defined and precisely variable conditions from the cold neutron beam. Therefore the spectra and angular distributions of the emerging decay particles will be distortion-free on the level of 10-4, more than 10 times better than achieved today. PERC is part of a priority program SPP 1491 "Precision experiments in particle and astrophysics with cold and ultra-cold neutron"(FWF, Contract No. I 534-N20)

Speaker: Mr Xiangzun Wang (TU Wien, Atom Institute)

75 Status of ³He-Magnetometry

For the measurement of the electric dipole moment of the free neutron it is important to know the exact magnetic field inside the EDM spectrometer. This field can be measured in-situ by monitoring the spin-precession of polarized ³He. At the institute of physics of the university of mainz a compact polarizer unit for ³He is under construction. The ³He will be polarized, compressed and filled in two magnetometer vessels inside the EDM chamber. The poster shows the actual status of the polarizer developments in mainz and also first results a test setup installed at the OILL in November 2009 where the ³He spin precession was measured for first time with laser pumped cesium magnetometers from FRAP inside an EDM shield. It will be also demonstrated, that the vertical net magnetization and the Bloch-Siegert Shift of the ³He magnetization don’t have any big influence on the UCNs.

Speaker: Andreas Kraft

76 Systematics calculations for the nEDM experiment at PSI

G. Zsigmond for the nEDM collaboration Paul Scherrer Institut, CH-5232 Villigen PSI The nEDM experiment at PSI is the flagship project at the new ultracold neutron (UCN) source at PSI which is in the commissioning phase. Estimations of systematic effects for the determination of the neutron EDM are an important part of this project. Experimental studies are accompanied by Monte Carlo simulations. Aim is to develop a realistic model of the nEDM apparatus, also implementing (inhomogeneous) magnetic fields and the Ramsey method of separated oscillatory fields. In this presentation, computations will be shown on the time evolution of the height difference of the centres of mass of the ultracold neutrons and mercury atoms, the latter serving as cohabiting magnetometer in the precession chamber. This centre of mass offset is caused by gravity and the large speed difference between UCN (~5 m/s) and Hg atoms (~150 m/s). This offset determines the ratio of precession frequencies measured for UCN and mercury atoms as function of a vertical field gradient [1]. By computing this centre of mass offset as function of storage times, consistency tests for magnetometer measurements of the vertical (most important) field gradient can be performed. This method also provides a possibility to determine the gyromagnetic ratio of the neutron. Furthermore, the transversal depolarization time constant (T2) can be estimated as function of field gradients and of simulated positional autocorrelation functions [2], also serving as crosscheck for measurements. [1] C.A. Baker et al., Pys. Rev. Lett 97 (2006) 131801 [2] D.D. McGregor et al., Pys. Rev. A 41 (1990) 2631

Speaker: Dr Geza Zsigmond (Paul Scherrer Institut)

Poster ZsigmondPosterPSI2010_v2.pdf

77 Test of Lorentz invariance with spin-polarized ultracold neutrons

The concept of symmetry plays a central role in our current understanding of physics at its most fundamental level. The invariance of physical laws under rotation symmetry is perhaps the most basic example, and for such it is worthwhile to test its validity with high accuracy. Deviation from rotation symmetry would reveal features of the new physics at very high energy scale, such as the Planck scale. High precision measurements can be performed on ultracold neutrons spins using UCN spectrometers, normally dedicated to the search for the Electric Dipole Moment. We present experimental null results concerning the search for a cosmic axial field acting on neutron spin, as well as the search for a Pockels-like effect of the vacuum.

Speaker: Dr Guillaume Pignol (LPSC Grenoble)

Poster LorentzUCN

78 Towards a new study of the electron-neutrino angular correlation in the decay of magneto-optically trapped 6He

Studies of nuclear beta decay have a long standing history in testing the Standard Model of particle physics. With the dominant (V-A) structure of the weak interaction determined, measurements of the angular correlation between the electron and neutrino momenta in nuclear beta decay can be used to search for scalar and tensor contributions to the weak interaction. The current best measurement on the electron-neutrino angular correlation coefficient in the decay of 6He dates back to 1963 by measuring the energy spectrum of the recoiling 6Li nucleus and amounts to -0.3343 +/- 0.0030 [1]. Its compatibility with the Standard Model expectation allows to constrain tensor contributions to (|C_T|^2+|C'_T|^2)/(|C_A|^2+|C'_A|^2)<0.4%. We intend to improve on this measurement by confining 6He atoms in a magneto-optical trap and detecting the recoiling nucleus and emitted electron in coincidence. The foreseen sensitivity in the measurement of the angular correlation coefficient will be approximately 0.1%. Here, we will present the details and current status of the experiment focussing on the performance of the 6He production and the magneto-optical trapping of the 6He atoms. [1] C. H. Johnson, F. Pleasonton and T. A. Carlson, Phys. Rev. 132, 1149 (1963).

Speaker: Andreas Knecht (University of Washington)

Poster 6He_poster.pdf

79 UCN detection with 6Li doped glass scintillators

Precision experiments at the high intensity UCN sources of new generation either planned or under construction around the world, call for the development of new UCN detectors with higher counting rate capabilities. In this context, several studies including solid state semiconductors, gas detectors as well as scintillator detectors, have recently been reported [1-4]. For the nEDM experiment at PSI, we have developed fast detectors based on 6Li doped glass scintillators (GS). A novel detector, made of a 6Li depleted GS30 glass stuck to the front of a 6Li enriched GS20 glass, has been tested. With such a combination, the edge effects, inherent to low energy neutron detection, are suppressed. As a result, a clear separation between the gamma and the neutron contributions is observed. The rate capability of the GS scintillators is in order of a few 105 UCN/s limited by the photomultiplier. In order to be able to count up to a few 106 UCN/s, a multidetector made of nine channels has been carried out. A new FASTER acquisition system has been developed to handle such high counting rates. The first tests performed at the ILL PF2/TEST beam line with the whole system are successful and are reported here.

Speaker: Mr thomas lefort (University of Caen)

Poster poster_PSI2010.pdf

Wednesday 13 October

Session We - 1

80 Lepton flavor violation and CP violation in SUSY

Speaker: Paride Paradisi

81 Interaction of electromagnetic and matter-waves with linear accelerating matter

It was found theoretically almost 30 years ago that the wave number and frequency change when the wave passes through an accelerating sample of a refractive medium. K. Tanaka [1] was the first to show it for the case of light optics. Later the same result was obtained for neutron waves [2-4]. More generally, a refractive index may be introduced for waves of any nature and the only requirement is the presence of scatterers in the medium. Therefore, particles of any nature should change their energy passing through the bounded volume of accelerating medium [5,6] and one can speak about very general Accelerating Matter Effect (AME). It was found later [6], that AME very closely relates with equivalence principle and can be generated not only by an acceleration of a bounded volume of matter but also by a spatial region characterized by the presence of a force field. It is worth noting that the Tanaka effect for light is so small that despite the fantastic sensitivity of modern optical methods, it has not been observed yet. However, the neutron-optics experiment of this kind appeared to be feasible and was performed with Ultra Cold Neutrons (UCN) [5.6]. The results of these spectroscopic experiments as well as description of new time of flight experiment will be presented in the report. The maximum value of the energy transform in these experiments was equal to ± (2÷6) ×10-10 eV . Results testify that the effect correspond to theoretical predictions with accuracy better than 10%. Some future possibilities for the investigation of the AME and its possible manifestation in astrophysical phenomena will be also discussed. References 1. Tanaka K. Phys. Rev. A. 25 (1982) 385. 2. Kowalski F. V. Phys. Lett. A. 182 (1993) 335. 3. K. C. Littrell, S. A.Werner, and B. E. Allman, J. Phys.Soc. Jpn., Suppl. A 65, (1996) 98. 4. Nosov V. G., Frank A. I. Phys. At. Nucl., 61 (1998) 613. 5. A.I. Frank, P.Geltenbort, G.V.Kulin, et al. JETP Letters, 84 (2006), 105. 6. A.I. Frank, P.Geltenbort, M. Jentschel, et al. Phys. At. Nucl., 71 (2008) 1656

Speaker: Prof. Alexander Frank (FLNP JINR, Dubna, Russia)

82 Eotvisch-type experiment with cold neutron

The crystal-diffraction experiment to test a weak equivalence principle for the neutron will be discussed. It is based on an essential magnification of an external affect on neutron diffracting by Laue for the Bragg angles close to right one. Factor of diffraction enhancement for the neutron trajectory "curvature" due to external field can reach magnitude about ~(10^8 - 10^9) in comparison with a free neutron. Accuracy to measure the ratio of inertial to gravitational neutron masses can reach ~10^{-6}, that is about two orders higher than best modern result.

Speaker: Dr Vladimir Voronin (Petersburg Nuclear Physics Institute)

Slides Ngrav_psi_2010.pdf

83 Trap with ultracold neutrons as a detector of dark matter particles with long-range forces

The possibility of using a trap with ultracold neutrons as a detector of dark matter particles with long-range forces is considered. The basic advantage of the proposed method lies in possibility of detecting the recoil energy 10-7 eV. The restrictions on parameters of Yukawa type interaction potential between dark matter particles and a neutron are presented for different dark matter densities on the Earth. The assumption concerned with long-range interaction of dark matter particles and ordinary matter leads to a substantial enhancement of cross section at low energy. Consequently, there arises a possibility of capture and accumulation of dark matter in a gravitational field of the Earth. Rough estimation of accumulation of low-energy dark matter on the Earth is discussed. The first experimental restrictions for existence of dark matter with long-range forces on the Earth are presented.

Speaker: Prof. Anatolii Serebrov (Petersburg Nuclear Physics Institute)

Slides A.Serebrov_PSI2010.ppt

Coffee Break

Session We - 2

84 From muonic hydrogen to muonic helium

The present discrepancy concerning the proton radius values extracted from hydrogen spectroscopy, scattering experiments and muonic hydrogen is discussed. Recent arguments about proton shape and new scattering data are presented. In addition we will conclude proposing a new experiment which could help to understand the discrepancy: the Lamb shift in muonic helium.

Speaker: Aldo Antognini

85 The Lamb shift in muonic hydrogen

The charge radius r_p of the proton has so far been known from electron-proton scattering with an astonishingly low precision of about 2%. The CODATA value of r_p with an uncertainty of 1% is mainly determined from hydrogen (H) spectroscopy data and bound-state QED calculations. The less accurate H-independent value from e-p-scattering limits the test of bound-state QED in hydrogen, as well as the accuracy in the determination of the Rydberg constant R. Muonic hydrogen (mu-p, i.e. a proton orbited by a negative muon) provides an elegant way to improve the uncertainty of r_p: The 2S Lamb shift is altered by as much as 2% due to the finite size of the proton. We have recently measured the Lamb shift in mu-p by laser spectroscopy of the 2S_{1/2}^{F=1} - 2P_{3/2}^{F=2} transition. Using present QED calculations for mu-p we determine r_p with a relative uncertainty of 8 10^{-4}. This new limit is imposed by theory (mainly the proton's polarizability) - the experimental data could provide a twice better uncertainty on r_p. The new value of r_p is 10 times more precise, but it deviates by 5.2 sigma from the present CODATA value, and 3.1 sigma from the value obtained by electron-proton scattering. The origin of this uncertainty is yet unknown. If it comes from QED calculations in mu-p, a term as large as 1.6 10^{-3} of the total Lamb shift must be missing. This is to be contrasted to the claimed accuracy of the calculations of 2.4 10^{-5}. Alternatively, the problem could come from hydrogen spectroscopy or from the calculation of the Lamb shift in hydrogen. Assuming for now the correctness of the calculations we can use the very accurately determined 1S-2S transition frequency in H, and our new r_p, to determine the Rydberg constant R with 4.6 times smaller uncertainty [1.5 ppt], but 5 sigma away from the CODATA value. We have also recorded a second resonance line in muonic hydrogen. The data is still being analyzed, but a preliminary analysis confirms the value of r_p deduced by the first resonance in mu-p. From this seconds resonance we will deduce the 2S hyperfine splitting in mu-p. We will be able to determine the Zemach radius (radius of the magnetic moment distribution) of the proton with a few per cent accuracy. In addition, we have observed three resonances in muonic deuterium. We will be able to give a deuteron charge radius and/or the deuteron polarizability, complementing isotope shift measurements in ordinary hydrogen and deuterium.

Speaker: Aldo Antognini

86 Pionic Hydrogen

K X-rays from pionic hydrogen and deuterium as well as muonic hydrogen have been measured using a high-resolution crystal spectrometer at the E5 beam line of PSI. From the ground-state level shifts and broadenings of the hydrogen isotopes, caused by the strong interaction, low-energy parameters of QCD become accessible as are the pion-nucleon scattering lengths and the threshold production strength of pions in nucleon-nucleon collisions. Muonic hydrogen allows important insights in the deexcitation cascade of such exotic atoms, the understanding of which is essential for a precision determination of the above-mentioned quantities. First experimental results are discussed in the context of recent results from theoretical efforts within the approach of Chiral Pertubation Theory and atomic cascade calculations.

Speaker: Detlev Gotta (Forschungszentrum Jülich)

Slides PSI_2010_piH_Gotta.pdf

87 Measurement of the ground-state hyperfine splitting of antihydrogen

The hydrogen atom is one of the most extensively studied atomic systems, and its ground state hyperfine splitting (GS-HFS) at 1.42 GHz has been measured with an extremely high precision of 10^-12. Therefore the antimatter counterpart of hydrogen, the antihydrogen atom, consisting of an antiproton and a positron, is an ideal laboratory for studying the CPT symmetry. Kostelecky and his colleagues created an extension to the standard model by introducing parameters into its Lagrangian which violate either the CPT symmetry or the Lorentz invariance [1]. These parameters have a dimension of energy (or frequency), therefore their model claim that it is not the relative but the absolute precision of a measurement which matters when doing a CPT test. Thus by measuring a relatively small quantity on the energy scale (like the 1.42 GHz GS-HFS), a smaller relative accuracy is needed to reach the same absolute precision. This makes a determination of the GS-HFS frequency with a relative accuracy of 10^-4 competitive to the measured relative mass difference of 10^-18 between the neutral kaon and antikaon, which is often quoted as the most precise CPT test so far. The ASACUSA collaboration at CERN's Antiproton Decelerator (AD) plans to measure the antihydrogen GS-HFS in an atomic beam apparatus [2,3] similar to the ones which were used in the early days of hydrogen HFS spectroscopy. The apparatus will use antihydrogen atoms produced in a superconducting cusp trap (i.e. anti-Helmholtz coils). The inhomogeneous magnetic field of such a trap will create a partially polarized beam, which will then pass through a radiofrequency resonator to flip the spin of the antihydrogen atoms. Finally a sextupole magnet analyses the spin orientation of the atoms. Simulations showed that such an experiment is feasible if appr. 100 antihydrogen atoms per second can be produced in the ground state, and that an accuracy of appr. 10^-7 can be reached within reasonable measuring times [3]. [1] R. Bluhm, V.A. Kostelecky, N. Russell, Phys. Rev. Lett. 82 (1999) 2254. [2] ASACUSA collaboration, Proposal CERN-SPSC 2005-002, SPSC P-307 Add. 1, 2005. [3] B. Juhasz, E. Widmann, Hyp. Int. 193 (2009) 305.

Speaker: Dr Bertalan Juhasz (Stefan Meyer Institute for Subatomic Physics, Vienna, Austria)

Slides juhasz_psi2010_talk.pdf

88 Towards antihydrogen spectroscopy at ALPHA

Spectroscopy of antihydrogen has the potential to yield high-precision tests of the CPT theorem and shed light on the matter-antimatter imbalance in the Universe. We will describe the progress made in the production of a trapped sample of antihydrogen atoms at CERN's Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms.We will report results from ALPHA's recent data-taking run and outline the prospects for the near future.

Speaker: Dr Arthur Olin (TRIUMF/UVic)

Slides pfsi_alpha.pdf

lunch

Session We - 3

89 EDM Searches and Their Cosmological Implications

New searches for the permanent electric dipole moments of the neutron, atoms, and nuclei are poised to probe CP-violation beyond that of the Standard Model with unprecedented sensitivity. This CP-violation may provide one of the keys to explaining the cosmic baryon asymmetry . I discuss the theoretical interpretation of EDM searches and their possible implications for the origin of matter.

Speaker: Prof. Michael Ramsey-Musolf (U. Wisconsin-Madison)

Slides PSI_Fall_10.pdf

90 The CryoEDM Experiment at ILL

The CryoEDM collaboration is building an experiment to measure the electric dipole moment (EDM) of the neutron with a precision, initially, of ~3 x 10^{-27} e.cm, and ultimately up to an order of magnitude beyond that. The experiment relies upon superthermal production of ultracold neutrons within a volume of superfluid helium, held at a temperature of 0.5 K. The Ramsey technique of separated oscillatory fields will be used to determine the Larmour precession frequency of batches of ultracold neutrons within a highly uniform and constant magnetic field: changes in this frequency that are proportional to the strength of an electric field applied parallel or antiparallel to the magnetic field are indicative of an EDM. This presentation will discuss the progress to date and the future development plans of this experiment, including some details of the potential systematic uncertainties. This presentation is given by the author on behalf of the CryoEDM collaboration.

Speaker: Prof. Philip Harris (University of Sussex)

Slides 101013_PSI.ppt

91 Recent Results from a Search for the Permanent Electric Dipole Moment of Mercury Atoms

Observation of a nonzero EDM would imply CP violation beyond the Standard Model. Additional sources of CP violation are expected to help explain the matter-antimatter asymmetry observed in our universe and naturally arise in extensions to the standard model such as supersymmetry. Our group has recently reported a new upper limit: |d_{Hg}| < 3.1 x 10^{-29} e-cm for the EDM of 199Hg. The experiment compared the spin precession frequencies in four spin-polarized Hg vapor cells: two cells lie in parallel magnetic and anti-parallel electric fields, resulting in EDM-sensitive spin precession while the remaining two cells, at zero electric field, serve to cancel noise generated by magnetic field gradients and test for systematic errors. A frequency shift, linear in the applied electric field, due to the Stark mixing ofatomic states has been identified and measured. A description of the EDM experiment and measurements that led to our recent result will be presented. This work was supported by NSF Grant PHY-0457320 and the DOE Office of Nuclear Science.

Speaker: Prof. Blayne Heckel (University of Washington)

92 Measuring the electron electric dipole moment in YbF

Certain paramagnetic molecules strongly amplify the electric dipole moment (edm) of the electron. There are now a number of molecular edm experiments underway worldwide. At the present, the experiment at Imperial College London using a molecular beam of YbF is the most advanced. Our current data set has a statistical uncertainty which is below the existing limit on the electron edm. I will discuss these latest results, paying particular attention to our data analysis techniques and possible systematic effects which might mimic an edm.

Speaker: Dr Ben Sauer (Imperial College London)

Slides eEDM_PSI2010_Sauer.ppt

Coffee Break

Session We - 4

93 EDM project at KEK-RCNP and TRIUMF

We have constructed a spallation UCN source of superfluid helium at RCNP. We obtained a world competitive UCN density at a proton beam power of 1 micro A and 390 MeV. By using this UCN source we will measure nEDM. We will discuss the present status of the UCN source and the preparation of EDM measurement. We will also discuss the future possibility at TRIUMF.

Speaker: Prof. Yasuhiro Masuda Masuda (Institute of Particle and Nuclear Studies, KEK)

94 Test of Gravitation with Quantum Objects

This talk is about a test of gravitation at small distances by quantum interference deep into the theoretically interesting regime of 10000 times gravity. The method allows a precise measurement of quantum mechanical phase shifts of a Schrödinger wave packet bouncing off a hard surface in the gravitational field of the earth. The experiment is sensitive to gravity-like forces at a length scale below 10 µm. Such forces can be mediated from gauge bosons propagating in a higher dimensional space and this experiment can therefore test speculations on large extra dimensions of sub-millimetre size of space-time or the origin of the cosmological constant in the universe, where effects are predicted in the interesting range of this experiment and might give a signal in an improved setup.

Speaker: Hartmut Abele (Atominstitut)

95 Precision measurements of the beta-asymmetry parameter in nuclear beta decay as a probe for tensor-type weak currents.

Correlation measurements in nuclear and neutron beta-decay are a powerful tool to probe the structure of the weak [Sev2006]. While neutron decay experiments mainly focus on the determination of the V_ud matrix element[Abe2008], correlation experiments in nuclear beta-decay concentrate on exotic weak interaction types [Beh2009][Sev2006]. The main advantage of nuclear beta-decays is the wide variety of transitions. For example, the beta-asymmetry parameter of a pure Gamow-Teller transition is well suited to search for a tensor-type weak interaction. Here, we will present the beta-asymmetry parameter of the pure Gamow-Teller decays of 114In and 60Co. Our results are the most accurate available today for nuclear decays. They are in agreement with the Standard Model and set limits on tensor-type charged weak currents. After being implanted or diffused into a metallic host foil, the radioactive 114In and 60Co nuclei were polarized with the Low-Temperature Nuclear Orientation (LTNO) method. A 3He/4He dilution refrigerator was used to cool the nuclei to milliKelvin temperatures, while an external magnetic in combination with an internal magnetic hyperfine field provided the polarizing field. The beta-particles were observed using Si or high-purity Ge detectors, which were mounted on the inside of the 4 Kelvin radiation shield, directly facing the sample foil[Wau2009c]. Extensive GEANT4 simulations were performed to gain control over the systematic effects, mostly scattering of beta-particles, which used to limit the precision of these type of experiments to several percent[Wau2009d]. The recoil corrections on the beta-asymmetry parameter of these isotopes were addressed for the first time, enabling us to interpret our results in terms of non-Standard Model physics. [Sev2006] N. Severijns, M. Beck and Oscar Naviliat-Cuncic, Review of Modern Physics 78 (2006) 991 [Abe2008] H. Abele, Progress in Particle and Nuclear Physics 60 (2008) 1 [Beh2009] J.A. Behr and G. Gwinner, Journal of Physics G 36 (2009) 033101 [Wau2009a] F. Wauters et al., Physical Review C 80 (2009) 062501 [Wau2009b] F. Wauters et al., to be published [Wau2009c] F. Wauters et al., Nuclear Instruments and Methods A 604 (2009) 563 [Wau2009d] F. Wauters et al., Nuclear Instruments and Methods A 609 (2009) 156

Speaker: Dr Frederik Wauters (IKS - Kaholieke Universiteit Leuven)

Slides PSI2010_Wauters.pdf

96 WITCH: a Precision Experiment for Weak Interaction Studies

The WITCH set-up (Weak Interaction Trap for CHarged particles) that was installed at ISOLDE/CERN combines a double Penning trap system to store radioactive ions and a retardation spectrometer to probe the energy of the daughter recoil ions. The primary aim is to search for scalar and/or tensor interactions in nuclear beta decay by precisely determining the beta-neutrino angular correlation coefficient, a. This can be extracted from the measured energy spectrum of the recoiling nuclei after beta decay. The set-up is now operational and the first recoil ion spectrum was measured in the decay of 124In. Although statistics were not sufficient and systematic effects have not yet been addressed in sufficient detail to extract weak interaction information, the charge state distribution of the recoiling 124Sn daughter ions could be derived from this. The set-up was upgraded (better vacuum, buffer gas purification, electropolished electrodes) and further optimized to allow for measurements with the mirror nucleus 35Ar. A first such measurement was already performed and allowed the investigation of systematic and unwanted effects in the system. At present the system is being optimized to allow for a longer measurement on 35Ar where useful physics information can be obtained.

Speaker: Martin Breitenfeldt (Katholieke Universiteit Leuven)

Slides PSI2010-10-13_Breitenfeldt.pdf

97 Measurement of the beta-neutrino angular correlation in the decay of trapped $^6$He$^+$ ions

Within the frame of the Standard Model, the weak interaction is mediated by the W+, W-, and Z0 bosons, which can only involve vector and axial vector interactions. The precise measurement of the beta-neutrino angular correlation, $a_{\beta\nu}$, in nuclear beta decay is a direct and sensitive tool to search for other Lorentz invariant contributions, such as Tensor and Scalar couplings. Considering the pure Gamow-Teller transitions, the most precise measurement achieved so far [1] has given rise to a relative uncertainty of 1% on $a_{\beta\nu}$, limiting a possible Tensor contribution at the level of 10%. In that experiment, the $a_{\beta\nu}$ coefficient was inferred from the integrated recoil energy spectrum of the $^6$He decay. The LPCTrap experiment [2] has been designed to perform a new measurement in $^6$He with a better control of the potential sources of systematic errors and a higher precision on $a_{\beta\nu}$. In this second generation setup, the decaying $^6$He$^+$ ions are trapped nearly at rest in vacuum, and the beta particle is detected in coincidence with the recoiling daughter nucleus. The analysis of the first data taking period at GANIL has provided a new value of $a_{\beta\nu}$ with a total relative uncertainty of 3%. In a more recent experiment, which is currently under analysis, the statistics has been improved by nearly two orders of magnitude, and thus, a better constraint on the Tensor contribution is expected. [1] C.H. Johnson, F. Pleasonton, and T.A. Carlson, Phys. Rev. 132 (1963) 1149. [2] X. Fléchard et al., Phys. Rev. Lett. 101 (2008) 212504.

Speaker: Dr Xavier Flechard (LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, Caen, France)

Slides FLECHARD_PSI2010.pdf

Conference Dinner

Thursday 14 October

Session Th - 1

98 Experimental tests of quantum mechanics (Pauli Exclusion Principle and spontaneous collapse model)

Experimental undergoing tests of the Pauli Exclusion Principle violation will be presented, together with future plans to measure the spontaneous emission of X rays predicted in collapse models. We present a method of searching for possible small violations of the Pauli Exclusion Principle (PEP) for electrons, through the search for "anomalous" X-ray transitions in copper atoms, produced by "fresh" electrons (brought inside the copper bar by circulating current) which can have the probability to do the Pauli-forbidden transition to the 1 s level already occupied by two electrons. We describe, then, the VIP (VIolation of PEP) experiment, in data taking since 2006 at the Gran Sasso underground laboratories. The goal of VIP is to test the PEP for electrons with unprecedented accuracy, down to a limit in the probability that PEP is violated at the level of 10**-29 - 10**-30, improving the previous limit by 3-4 orders of magnitude. We report preliminary experimental results and briefly discuss some of the implications of a possible violation, together with future plans to gain other 2-3 orders of magnitude. We will then present a project to use a similar experimental technique to measure the spontaneously emitted X rays predicted in the framework of collapse models (GRW theory, dynamical reduction models). Such models were put forward alternatively to the "standard" quantum mechanics' Schrodinger equation, followed by a "alla von Neumann" collapse of the wave-function, implementing a (nonrelativistic) dynamical reduction/collapse models, by modifying with a non-linear and stochastic terms the Schrodinger equation. Baring on the importance of this conceptually new model(s), it is of utmost importance to study its experimental consequences, where the predictions are diverging from the standard equations, and to perform dedicated experiments to check it. Today there are very few and far from complete experimental information. We aim to perform a feasibility study for a dedicated experiment to check the collapse models.

Speaker: Dr Catalina Oana Curceanu (LNF-INFN)

99 Measuring the fall of antihydrogen: the AEGIS experiment at CERN

Experimental studies of Antihydrogen have a short history, but an ambitious future: a first generation of experiments, in which cold charged plasmas of positrons and antiprotons were combined, produced large numbers of antihydrogen atoms for the first time in 2002. These have given place to a second wave of experiments which are attempting the next steps of trapping and cooling antihydrogen atoms, with the long term goal of carrying out precision laser spectroscopy comparisons of the spectra of hydrogen and antihydrogen, and thus perform a precision test of the CPT symmetry. In parallel, advances in other fields have made possible the concept of a beam of antihydrogen atoms, which opens the door to measuring the gravitational interaction of (neutral) antimatter. The AEGIS experiment aims in a first step to reach a 1% precision on the gravitational interaction of antihydrogen by measuring its free fall over its parabolic trajectory. The experiment and the techniques involved will be discussed.

Speaker: michael doser (cern)

Slides PSI2010_workshop.pdf

100 A search for nEDM and new constraints on short-range "pseudo-magnetic" interaction of neutron with matter using new effects in neutron optics of noncentrosymmetric crystals

Here we will discuss new effects resulting from the recently predicted and discovered strong electric fields (up to 10^9 V/cm), which affect the neutrons moving in noncentrosymmetric crystals. Such fields depend on the value and direction of the neutron momentum and result in some new polarization phenomena observable in neutron diffraction and optics. That opens, for example, a new way for searching the electric dipole moment of a neutron (nEDM) with the sensitivity comparable or exceeding that for the most sensitive now magnetic resonance method using ultra cold neutrons (the current best limit of Dn 310^{-26}ecm (at 90% C.L.) obtained at the ILL reactor at Grenoble resulted the long-term efforts of PNPI and ILL groups). The new limits on the EDM value would be of great importance for understanding the nature of the CP violation as well as of the Universe baryon asymmetry. A series of experiments on neutron diffraction and optics was carried out in Gatchina at the PNPI reactor WWR-M to study the polarization phenomena in the noncentrosymmetric quartz crystals. Observed effects give a real prospects for a search for neutron electric dipole moment using the crystal diffraction technique with the comparable or better sensitivity as the UCN method. Recent test crystal-diffraction experiment on a search for neutron EDM carried out at ILL reactor has confirmed this conclusion. Also the direct constraint on the parameters of short range pseudomagnetic interaction of free neutron with matter is obtained from that test experiment. It is shown that this constraint on a product of scalar to pseudo-scalar coupling constants g_s g_p is better than that of any other method for the range  < 10^{-5}cm.

Speaker: Prof. Valery Fedorov (Petersburg Nuclear Physics Institute)

101 Noble gas EDM measurements and noble gas magnetometry

Spin-polarized noble gases have several attractive features for EDM measurements: 1) several species can be polarized simultaneously by spin-exchange optical pumping; 2) they can be contained in cells; 3) spin relaxation times can be long - minutes to hours providing narrow linewidths and high precision; 4) large signal to noise results from spin-polarization of high densities; 5) multiple species can provide co-magnetometry that can monitor or mitigate systematic effects arising from magnetic field fluctuations. For example, the spin-exchange pumped noble-gas maser has been used to measure the EDM's of 3He and 3Xe simultaneously with a sensitivity on the 129Xe EDM of about 3e-27 e-cm (Phys. Rev. Lett. 86, 22 (2001)). We have begun a program to improve this measurement with the goal of an order of magnitude improvement in sensitivity. Octupole collectivity can strongly enhance the atomic EDM because the nuclear Schiff moment depends on collective effects and on the polarizability, which in turn depends on small splitting of opposite parity nuclear states that arise in octupole deformed systems. 221Rn and 223Rn are good candidates for enhanced EDMs; however there is currently a paucity of data on the nuclear structure of these isotopes. We have initiated studies of the nuclear structure and octupole collectivity, and we have also developed apparatus to collect and polarize radon isotopes at TRIUMF (Vancouver, Canada) in preparation for Radon-EDM measurements. Noble gas species, specifically 129Xe, are also potentially ideal candidates for a co-magnetometer for ultracold neutron (UCN)-EDM experiments (replacing the 199Hg used in the most recent ILL measurement). 129Xe has a much smaller neutron-absorption cross section and may be cooled so that the trajectories are more similar to the UCN. We have developed a new two-photon magnetometry scheme that promises to provide precision magnetometry in a volume that contains spin-polarized 129Xe. The technique is currently being studied in an analogous two-electron system: 171Yb. When combined with an improved 129Xe EDM sensitivity, this provides an attractive comagnetometer for neutron-EDM measurements.

Speaker: Prof. Tim Chupp (University of Michigan)

Slides PSI2010Talk.ppt

102 Experimental search for 129Xe atomic EDM with nuclear spin maser technique

Electric dipole moment (EDM) of a particle violates P and T symmetries and serves as a definitive probe for new physics beyond the standard model of elementary particles. We plan to search for an EDM in a diamagnetic atom 129Xe, taking advantage of spin maser technique. In a conventional spin maser the spin precession is maintained by virtue of a feedback field that is generated by a coil coupled to the spin system. The feedback field in our maser is laboratory-composed according to an optically detected spin precession signal. From our previous studies on the operation of such a maser, it turned out that the major limiting factors on the frequency precision are drifts in the solenoid current and temperatures around the 129Xe gas cell. Thus we are presently developing a temperature stabilization system which circulates heat transporting fluid in order to suppress variation of temperature down to 0.1 degree. Also, the power of the pumping laser was found to be insufficient for the 129Xe nuclear spins to be fully polarized. We have introduced a high power laser with a reduced line width, with which an improved stabilization of the maser operation is expected. In addition, gas cells equipped with transparent electrodes for application of an electric field is being prepared. We will report on results of such developments attempting improved maser frequency precision, and discuss future prospect of our 129Xe EDM search experiment.

Speaker: Mr Takeshi Inoue (Tokyo Institute of Technology)

Slides PSI2010_T_Inoue_PDF.pdf

Coffee Break

Session Th - 2

103 from Silicon-, via Gas-, towards Foil tracking detectors

The GridPix detector is a Time Projection Chamber with a pixelized readout anode. With a drift gap of 1 mm, the gas layer functions as the Si sensor of a Si pixel or Si strip detector. With a drift gap of 20 mm, GridPix can accurately reconstruct the path of, and measure the energy of photo- and Compton electrons associated with photon absorption. With this information, the polarization of the photons can be obtained. The application of GridPix in bi-phase LAr or LXe WIMP-search experiments is under study. The essential gas amplification occurs in the gap between the Integrated Grid (InGrid), made by means of MEMS technology, and the pixel chip. The same MEMS technology can be applied for creating a stack of grids. By putting the grids on decreasing potentials, they could act as dynodes of a photomultiplier. In this way, a thin and flat electron multiplier could be made. In another development, the emission of low-energetic electrons from a surface, due to the passage of a charged particle, is under study. With low work function materials (CsI, diamond, Si-nitride), combined with a fractal-like increase of the effective surface, high-efficiency Electron Emission Foils may be feasible.

Speaker: Dr Harry van der Graaf van der Graaf (Nikhef)

104 A New High-Sensitivity Muon-to-Electron Conversion Search at Fermilab

Mu2e will search for coherent, neutrino-less conversion of muons into electrons in the field of a nucleus, witha sensitivity improvement of a factor of 10,000 over existing limits. Such a lepton flavor-violating reaction probes new physics at a scale unavailable by direct searches at either present or planned high energy colliders. The physics motivation for Mu2e will be presented, as well as the design of the muon beamline and spectrometer. A scheme by which the experiment can be mounted in the present Fermilab accel- erator complex will be described. Prospects for increased sensitivity from the Project X linac that is being proposed by Fermilab will be discussed.

Speaker: Dr Robert Bernstein Bernstein (Fermilab)

Slides psi_mu2e.pdf

105 Ultraslow muonium for a muon beam of ultrahigh quality

A new pathway for the achievement of a pulsed slow muon beam by the muonium ionization method is proposed. It uses a thin superfluid helium target in which the stopped muons are pulled towards the liquid vapor interface where they form muonium atoms in the bubble state. As they reach the interface they are emitted and slow down in a vapor layer from which they exit at low velocity and low divergence. Compared to existing schemes, the requirements on the power of the Lyman alpha 1s-2s excitation laser are significantly reduced and an outgoing muon beam of many orders of magnitude better phase space quality is achieved.

Speaker: Dr David Taqqu (Swiss federal institute of technology, Zurich)

106 A novel mu to 3e experiment

Design studies for an experiment searching for the lepton flavour violating decay mu to 3e are presented. The detector concept is based on thin layers of silicon sensors with fast readout. The aim is to reach an experimental sensitivity of 1e-16 for this process, which is an improvement by factor 10000 compared to the existing limit.

Speaker: Prof. Andre Schoening (University Heidelberg, Institute of Physiscs)

Slides NovelMuEEE.pdf

107 Can CP-violation be observed in heavy-ion collisions?

We demonstrate that, at least at present, there is no convincing way to detect CP-violation in heavy-ion collisions.

Speaker: Prof. I. B. Khriplovich (Budker Institute of Nuclear Physics, 630090, Novosibirsk, Russia)

lunch

Session Th - 3

108 A large Muon Electric Dipole Moment from Flavor?

We study the prospects and opportunities of a large muon electric dipole moment (EDM) of the order 10^-24 ecm -- 10^-22 ecm. We investigate how natural such a value is within the general minimal supersymmetric extension of the Standard Model with CP violation from lepton flavor violation in view of the experimental constraints. In models with hybrid gauge-gravity mediated supersymmetry breaking a large muon EDM is indicative for the structure of flavor breaking at the Planck scale, and points towards a high messenger scale.

Speaker: Mr Timo Rüppell (Helsinki Institute of Physics)

Slides RuppellPSI2010.pdf

109 The New g-2 and Muon EDM experiment at Fermilab

The Brookhaven E821 experiment measured the muon's anomalous magnetic moment to a precision of 0.54 ppm. At this time, the standard model prediction is known to similar precision. When experiment and theory are compared, the difference exceeds 3 standard deviations in significance. What is this telling us? I will review the current status, the more popular interpretations, and most importantly, describe the effort of a new collaboration aiming to improve the experimental precision by more than a factor of 4. The new experiment will use the E821 storage ring, relocated to Fermilab, where the suite of beams and rings there offer a very attractive environment such that 20 times the statistics can be obtained in about 1 year of running. In addition to the g-2 measurement, a parasitic muon EDM test will be made, with the aim of up to 100 times improvement compared to E821.

Speaker: Prof. David Hertzog (University of Washington)

Slides PSI-Muon-g2-final.ppt

110 Search for EDMs Using Storage Rings

An electric dipole moment (EDM) aligned with the spin of a fundamental particle violates both parity conservation and time reversal invariance, or, via the presumed CPT conservation, CP invariance. Standard Model predictions are much below current or anticipated experimental sensitivity levels; an observation within the next generation of searches will represent a new signature of CP violation and possibly contribute to our understanding of the matter-antimatter asymmetry of the universe. This presentation outlines the possibility to use an electromagnetic storage ring to directly probe charged particles for an EDM at a sensitivity level approaching 10^-29 e.cm. Every sensitive electric dipole moment measurement proceeds in three steps: preparation of an intense highly polarized ensemble of particles; interaction of the EDM with a strong electric field for as long as possible; measurement of the spin evolution. For the storage ring technique, a polarized beam is accelerated and injected into the storage ring. Here the polarization is rotated to point along the momentum of the particles. While circling the ring the particles interact with a combination of a vertically oriented magnetic field and a radially oriented electric field. With a carefully controlled combination of electric and magnetic field strengths, the precession of the polarization caused by the interaction of the magnetic moment can be halted. The interaction between the EDM and the electric field causes the polarization to develop a vertical component, out of the ring plane. The setup, status and R&D efforts of several experimental EDM searches based on the storage ring technique will be discussed, including those on the muon, proton and deuteron.

Speaker: Detlev Gotta

Slides PSI_SPIN_EDM_2010.pdf

111 Search for a neutron EDM at SNS

The nEDM Collaboration is developing an experiment to run at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory to search for the neutron electric dipole moment (EDM) with a sensitivity of <10^{-27} e cm based on the scheme proposed by Golub and Lamoreaux. The collaboration has been working on various R&D experiments to establish the technical feasibility of the experiment and to guide the design of the apparatus. The collaboration has also been working towards finalizing the engineering of the experimental apparatus. In this talk, the principle of the experiment and the status of the project will be presented.

Speaker: Dr Takeyasu Ito (Los Alamos National Laboratory)

Slides Ito_PSI2010.pdf

112 The search for the neutron electric dipole moment at the Paul Scherrer Institut

The measurement of the neutron electric dipole moment (nEDM) constrains the contribution of CP-violating terms within both the standard model and its extensions. The limit, or even the observation of an EDM would also add profoundly to the understanding of the baryon-asymmetry of the universe. The experiment set up at the Paul Scherrer Institut (PSI), Switzerland, uses ultra-cold neutrons (UCN) stored in vacuum at room temperature. This technique provided all previous limits including the last (and best) one by the RAL/Sussex/ILL collaboration in 2006: dn<2.9 10-26 e cm (90% C.L.). We aim at improving the experimental sensitivity by a factor of 5 within 2-3 years, using an upgrade of the same apparatus. We will take advantage of the increased ultra cold neutrons density at PSI and of a new concept including both, an external magnetometry and a co-magnetometer. In parallel, a next generation apparatus with two UCN storage chambers and elaborate magnetic field control is being designed aiming at another order of magnitude increase in sensitivity, allowing to put a limit as tight as dn<5 10-28 e cm if not establishing a finite value. The status of both projects will be given.

Speaker: Dr Stephanie Roccia (KUL Leuven)

Slides RocciaPSI2010.pdf

113 Concluding Remarks

Speaker: N. N.

Coffee Break

Tour of PSI - Facilities