Conveners
Session: Mo - 1
- Convener: Geoffrey Greene
Session: Mo - 2
- Convener: Stephanie Roccia
Session: Mo - 3
- Convener: Georg Bison
Session: Mo - 4
- Convener: Niklaus Berger
Session: Tu - 1
- Convener: Dieter Ries
Session: Tu - 2
- Convener: Angela Papa
Session: Tu - 3
- Convener: Sonia Bacca
Session: Wd - 1
- Convener: Peter Kammel
Session: Wd - 2
- Convener: Gilberto Colangelo
Session: Wd - 3
- Convener: Klaus Jungmann
Session: Wd - 4
- Convener: Beatrice Franke
Session: Th - 1
- Convener: Philipp Schmidt-Wellenburg
Session: Th - 2
- Convener: Eberhard Widmann
Session: Th - 3
- Convener: Anna Soter
Session: Th - 4
- Convener: Michael Jentschel
Session: Fr - 1
- Convener: Satoshi Mihara
Session: Fr - 2
- Convener: Sacha Davidson
Charged-lepton flavour-violating (cLFV) processes provide a unique discovery potential
for physics Behind Standard Model (BSM). These cLFV processes explore new physics parameter space in a manner complementary to the collider, dark matter, dark energy, and neutrino physics programmes. Furthermore the observation of neutrino oscillations has clearly demonstrated that neutral lepton flavour is...
The striking imbalance of matter and antimatter in our universe is one of the hottest topics of modern physics, which inspires experiments to compare the fundamental properties of matter-antimatter conjugates at lowest energy and with great precision. The BASE collaboration at the antiproton decelerator of CERN is performing such high-precision comparisons with protons and antiprotons. Using...
Due to their outstanding property to be storable and hence observable for long periods of time (several hundreds of seconds) in suitable material or magnetic traps, ultracold neutrons (UCNs) with energies around hundred nanoelectron-volts are a unique tool to study fundamental properties of the free neutron, like its beta-decay lifetime, its electric dipole moment and its wave properties.
The...
The fact that the universe is made entirely out of matter, and contains no free anti-matter, has no physical explanation. While we cannot currently say what process created the matter in the universe, we know that it must violate a number of fundamental symmetries, including those that forbid the existence of certain electromagnetic moments of fundamental particles. We can search for...
We present our recently published [1] measurement of the CP-violating permanent Electric Dipole Moment (EDM) of the neutral $^{129}$Xe atom. Our experimental approach is based on the detection of the free precession of co-located nuclear spin-polarized $^3$He and $^{129}$Xe samples. The EDM measurement sensitivity benefits strongly from long spin coherence times of several hours achieved in...
We describe a new technique used to measure the EDM of 129Xe with 3He comagnetometry. Both
species are polarized using spin-exchange optical pumping, transferred to a measurement cell with doped silicon electrodes, and
transported into the BMSR2 magnetically shielded room at PTB-Berlin, where SQUID magnetometers detect free precession
in applied electric and magnetic fields. Two campaigns...
The decay K+→π+vv, with a very precisely predicted branching ratio of less than 10exp(-10), is one of the best candidates to reveal indirect effects of new physics at the highest mass scales. The NA62 experiment at the CERN SPS is designed to measure the branching ratio of K+→π+vv with a decay-in-flight technique. NA62 took data so far in 2016-2018. Statistics collected in 2016 allowed NA62 to...
Neutrons are excellent probes to test gravity at short distances – electrically neutral and only hardly polarizable. Furthermore, very slow, so-called ultracold neutrons form bound quantum states in the gravity potential of the Earth. This allows combining gravity experiments at short distances with powerful resonance spectroscopy techniques, as well as tests of the interplay between gravity...
Steadily improving bounds on the neutron EDM provide stringent bounds on new interactions and theories at the TeV scale. To leverage this connection requires precise results on matrix elements of the Theta and novel CP violating interactions at the TeV scale. In this talk, I will update our results for the contributions of the quark EDM operator that are already being used in phenomenology,...
We live in a matter dominated Universe. Naively assuming a preference of nature for symmetries, it’s somewhat unexpected that we observe much larger amounts of matter over antimatter. Asking our very successful Standard Model of Particle Physics for insight on this Baryon Asymmetry in the Universe (BAU), we learn that the observed asymmetry is actually even much larger than expected - by...
We outline the principles of the method for searching for a neutron edm using super-thermal production of UCN in He4, a dilute solution of He3 as a co-magneotmeter and critical spin dressing and report on recent progress in designing and constructing the various sub-systems of the experiment.
The ultra-precise determination of the $g$-factor of highly charged ions is a unique possibility to test the validity of the Standard Model, particularly Quantum Electrodynamics (QED) in extreme electric fields up to $10^{16}$ V/cm. While the weak-field regime has been exquisitely tested, in the presence of strong fields higher-order contributions beyond the Standard Model might become...
The measurement of the Lamb shift in muonic hydrogen and the subsequent emergence of the proton radius puzzle have motivated an experimental campaign devoted other light muonic atoms, such as muonic deuterium and helium. For these systems nuclear structure corrections are the largest source of uncertainty and consequently the bottle-neck for exploiting the experimental precision to extract the...
Negative muons at rest quickly get captured by nearby atoms and subsequently de-exite via radiative and Auger transitions until the muon ends up in the 1s orbital. At the lower orbits, there is substantial overlap between the muon wave function and the nucleus, making this system an excellent laboratory to study the interaction between the muon and atomic nucleus. With a physics program...
Precision experiments on neutron beta decay are used to determine the CKM matrix element $V_{ud}$ and to search for novel scalar and tensor couplings beyond the axial-vector and vector couplings of the standard model. In this presentation, I will discuss the result of PERKEO III on the parity-violating beta asymmetry obtained using a pulsed cold neutron beam at the ILL. The result confirms...
We report on a precise measurement of the electron-antineutrino angular correlation (a coeffcient) in free neutron beta-decay from the aSPECT experiment. The a coefficient is inferred from the recoil energy spectrum of the protons which are detected in 4pi by the aSPECT spectrometer using magnetic adiabatic collimation with an electrostatic filter. Data are presented from a 100 days run at the...
When neutrons are Bragg diffracted from a crystal slab, Bloch waves form in the crystal. Interference between the Bloch waves cause oscillations in the diffracted beam whose phase is a function of neutron energy and the thickness of the crystal slab. This phenomenon is known as pendellosung interference and has a spatial period, called the pendellosung length, that is on the order of 50...
We report the parity violating proton asymmetry $A_p$ in the reaction $\vec{\mbox{n}}$ + $^{3}$He $\to$ p + $^{3}$H (the n-$^3$He experiment), the most precise hadronic asymmetry ever measured. Hadronic parity violation offers a unique probe of nucleon structure and the underlying non-perturbative behavior of low-energy QCD. The hadronic weak interaction is characterized by five spin and...
By means of laser spectroscopy we have measured several 2S-2P transitions in muonic hydrogen. From these measurements we have extracted a proton charge radius 20 times more precise than obtained from electron-proton scattering and hydrogen high-precision laser spectroscopy but at a variance of 7 sigma from these values. This discrepancy referred to as the ``proton radius puzzle’’ has prompted...
We have measured the Lamb shift in atomic hydrogen using a new FOSOF (Frequency Offset Separated Oscillatory Fields) method. We measure the 2S$_{1/2}$(F=0)-to-2P$_{1/2}$(F=1) interval to be 909.8717(32) MHz, from which an rms proton charge radius of 0.833(10) fm can be determined.
It is rare to have a discrepancy in such a basic property as proton size, and yet during the past decade measurements of proton charge radius using muons and electrons have disagreed by almost six standard deviations. The MUon proton Scattering Experiment (MUSE) at PSI aims to shed more light on this puzzle, by measuring the elastic scattering of muons, electrons, and positrons on protons in...
The extraordinary advances in quantum control of matter and light have been transformative for precision measurements with atoms. For example, the development of atomic clocks enabled searches for the variation of fundamental constants, dark matter, violations of Einstein equivalence principle, and other applications. I will give an overview of precision fundamental studies with atoms...
Clocks are devices that allow us to share time by taking advantage of ubiquitous oscillatory phenomena in nature. We once relied on astronomical observations, and today we use far regular oscillations of cesium atoms to define the international system of unit (SI) for time, i.e., the SI second. Recent optical atomic clocks have achieved 100-fold improvement over cesium clocks [1]. This extreme...
The ALPHATRAP $g$-factor experiment is a high-precision Penning-trap experiment located at the Max Planck Institute for Nuclear Physics in Heidelberg. It has been designed for performing high-precision $g$-factor measurements on heavy highly charged ions (HCI), such as hydrogenlike $^{208}\mathrm{Pb}^{81+}$ and boronlike $^{208}\mathrm{Pb}^{77+}$, which will be externally produced and injected...
Please find the abstract attached.
Relatively simple dynamics, and extremely well controlled radiative and loop corrections, ensure that pion and muon decays are described with unprecedented precision within the Standard Model, typically with relative uncertainties of $\sim 10^{-4}$ or lower. This theoretical precision makes the $\pi$ and $\mu$ decays suitable as a sensitive means of testing the underlying symmetries,...
Since the discovery of the muon, the lack of understanding of flavor is one of the most intriguing and persistent problems in particle physics. Many hypotheses which extend the Standard Model suggest that observations of non-universal charged current interactions could be due to effects at high mass scales, possibly approaching 1000 TeV, or to the existence of sterile neutrinos. Measurement of...
The Mu2e experiment at Fermilab will search for the neutrinoless conversion of a muon into an electron in the field of an aluminum nucleus. A clear signature of this charged lepton flavor violating coherent two-body process is the monoenergetic conversion electron of 104.97 MeV produced in the final state. The experiment will have a single-event sensitivity of ~$2\times 10^{-17}$, and either...
presented on behalf of the AlCap collaboration
Observation of neutrinoless muon-to-electron conversion in the presence of a nucleus would be unambiguous evidence of physics Beyond the Standard Model. Two experiments, COMET at J-PARC and Mu2e at Fermilab, are under construction and will search for this process with a detection sensitivity of $10^{-16}$, 10,000 times better than previously...
The fine-structure constant $\alpha$ is ubiquitous in physics, and a comparison among different experiments provides a powerful test of the Standard Model of particle physics. The most precise measurement of $\alpha$ (to date) is our recently published result, $α = 1/137.035\,999\,046(27),$ with an uncertainty of 200 parts per trillion (ppt). A $2.5-\sigma$ tension with the value obtained...
Recent improvements of the Large Hadron Collider luminosity and the beginning of Belle II experiment will increase the sensitivity to tau lepton-flavour violating modes. In particular, it has been claimed by Pham in hep-ph/9810484 that $BR(\tau \to 3 \mu)$ could be as large as $10^{−14}$ in the Standard Model with massive neutrinos, contradicting earlier predictions for $BR(\mu \to 3e)$. If...
Past years have seen an impressive progress in perturbative calculations. We apply these techniques to compute high-precision QED contributions to low-energy processes involving muons and other leptons.
In this talk, I will review the current situation.
The h(125) boson was discovered at the LHC in 2012, but as Run 2 has ended, nothing beyond the Standard Model (SM) has emerged, be it supersymmetry, extra gauge bosons, or any new particle. We call this situation, Dyssymmetry, as spoken by Nature. As such, we take the simplicity path to reexamine any presumed symmetries. In particular, we scrutinize the usual Z2 symmetry associated with having...
The MuSun experiment utilizes a unique cryogenic time projection chamber to extract the $\mu d$ capture rate to better than 1.5% precision via determination of the $10^{-3}$ deviation of the muon lifetime in deuterium gas from the free muon lifetime. This measurement will lead to a benchmark result in calibrating weak interactions in the two nucleon system, relevant for calculating fundamental...
The Muon g-2 experiment E989 at Fermilab will measure the anomalous magnetic moment of muon, a$^{}_\mu$, with a precision goal of 140 part-per-billion (ppb). The experiment is aiming to resolve the discrepancy of more than 3 standard deviations between the previous measurements dominated by the Brookhaven E821 result and the Standard Model calculation of a$^{}_\mu$.
The experimental concept...
In their 2004 paper, Melnikov and Vainshtein derive a short-distance constraint for the pseudoscalar-pole light-by-light four-point function. To satisfy this constraint, Melnikov and Vainshtein dropped the pseudoscalar transition form factor at the vertex where the external photon is hooked. We present a way to satisfy the short-distance constraint of Melnikov and Vainshtein with an infinite...
Some recent measurements of b-hadron decays at the LHCb experiment and B-factories show a discrepancy with respect to Standard Model expectations. They consists of test of lepton flavour universality in rare and semileptonic decays and measurements of rare semi-muonic decays. While each of these measurements has a limited statistical significance, intriguingly, they seem to form a coherent...
We consider possible beyond-the-Standard-Model (BSM) effects that can accommodate both the long-standing tension in the anomalous magnetic moment of the muon, aμ=(g−2)μ/2, as well as the emerging 2.5σ deviation in its electron counterpart, ae=(g−2)e/2. After performing an EFT analysis, we consider BSM physics realized above the electroweak scale and find that a simultaneous explanation becomes...
Measurement of free neutron decay to a proton, electron, and antineutrino provides information about the fundamental parameters of the charged weak current of the nucleon and constrains many extensions to the Standard Model at and above the TeV scale. Knowledge of the lifetime to an accuracy of better than 1 s is necessary to improve BBN predictions of elemental abundances and to search...
Precision measurements of the neutron lifetime provide stringent tests of the standard electroweak model [1] as well as crucial inputs for Big-Bang nucleosynthesis calculations [2]. When combined with measurements of other neutron beta decay correlation coefficients [1], the neutron lifetime enables the determination of the Vud element of the Cabbibo-Kobayashi-Maskawa quark mixing matrix,...
Gravitationally bound quantum states of ultracold neutrons, which have been measured using pixelated silicon imaging sensor for cold neutrons[1], would be an unique and interesting system to see gravity-like phenomena beyond Newtonian expressions or the general relativity. We are now designing and developing the experimental details to manipulate this quantum system to fit our planning...
The report is devoted to the evolvement of views at the Accelerating Medium Effect, which consists in changing the frequency of a wave passing through a refracting sample moving with acceleration. At different times, theoretical predictions of such a change in frequency were made for electromagnetic waves passing through a dielectric plate moving with acceleration [1], neutron waves passing...
It has been 20 years since the start of the Antiproton Decelerator (AD) facility at CERN. During this time, tremendous progress has been made in synthesizing, trapping, and interrogating cold antihydrogen atoms. The field of antihydrogen physics has now arguably advanced from the proof-of-principle stage to the precision physics stage. This talk will review recent progress, with some focus on...
The search for neutron-antineutron oscillations is currently of great interest as a process with baryon number violation. The results of the Monte Carlo simulations of the experiment based on the storage of ultracold neutrons in a material trap and of the experiment at cold neutron beam are presented. The possibilities of increasing the sensitivity of the experiment due to the accumulation of...
Recently proposed ultra-precise neutron spectrometry technique based on the effects of dynamic neutron Laue-diffraction in perfect crystals was experimentally tested.
This technique is based on the effect of enhancement of angular deviation of neutron trajectory inside the crystal when the angle of neutron incidence on the crystal is slightly varied. Moreover, there is an additional gain...
The Standard Model (SM) has become one of the most complete theories encapsulating fundamental particle interactions. Despite its far ranging success, neutrino flavor oscillations, the observed baryon asymmetry, the dark matter puzzle, and complete absence of gravity from the theory makes it clear that there must exist interactions and particles beyond the standard model (BSM). A nonzero Fierz...
Measurements of the $\beta^-$ spectrum of tritium give the most precise directly measured limits on neutrino mass. Cyclotron Radiation Emission Spectroscopy (CRES) is a new experimental technique that has the potential to surmount the systematic and statistical limitations of current-generation direct measurement methods and reach an effective electron antineutrino mass sensitivity of...
Experiment E36 has recorded stopped-kaon decay data at the J-PARC K1.1BR beamline for a precision measurement of the ratio of decay widths BR($K^+ \rightarrow e^+\nu_e$) and BR($K^+ \rightarrow \mu^+ \nu_\mu$), respectively, to test lepton universality, and to search for rare decay modes producing light neutral bosons. An overview of the experiment and analysis status will be...
Neutron beta decay is the simplest example of semi-leptonic decay. A precise measurement of the neutron lifetime and $\lambda$, the ratio of axial vector and vector coupling constants of the weak interaction, allow for a determination of the CKM matrix element $V_{ud}$ that is free from nuclear structure effects. The neutron lifetime provides an important test of unitarity and consistency of...
C. L. Morris for the UCNTau collaboration
A new method for counting surviving neutrons in neutron lifetime measurements, using bottled ultracold neutrons, which provides better characterization of systematic uncertainties and enables higher precision than previous measurement techniques will be described. An active detector that can be lowered into the trap has been used to measure the...
After the recent high precision determinations of $V_{us}$ and $V_{ud}$, the first row of the CKM matrix shows more than $4\sigma$ deviation from unitarity. Two possible scenarios beyond the Standard Model can be investigated in order to fill the gap. If a 4th quark $b'$ participates in the mixing, with $\vert V_{ub'} \vert \simeq 0.04$, then its mass should be no more than 6 TeV or so. A...
I will survey some of the recent experiments, including the Cosmic Axion Spin-Precession experiments (CASPEr), the use of sensor networks to detect topological dark matter, possibly trapped in the gravitational potential of the Earth, as well as experiments looking for scalar dark-matter fields oscillating at frequencies of up to hundreds of megahertz.
Some references can be found at:...
Very light and very weakly coupled particles, including in particular axion-like particles, provide interesting opportunities for dark matter. We consider a variety of different types of such light dark matter candidates and explore possible experimental and observational tests.
Neutrinos are the only known elementary particles that are Majorana fermion candidates, implying that they would be their own antiparticles. The most sensitive and perhaps only practical probe the Majorana nature of neutrinos is an extremely rate nuclear decay process, the neutrinoless double beta decay. I will present the experimental techniques to search for this decay, show current results...
Present status of experiment Neutrino-4 search for sterile neutrino is discussed. The effect of oscillations into sterile neutrino with parameters Δm$^2_{14}$$\approx$7.3 eV$^2$, sin$^2$2θ$_{14}$$\approx$0.39 is observed at the 2.8σ level. The detailed analysis of possible systematic errors is presented. Plans to improve the existing installation and create a new installation with a...
Experiments with muons ($\mu^{+}$) and muonium atoms ($\mu^{+}e^{-}$) offer several promising possibilities for testing fundamental symmetries of particle physics with high precision. Examples of such tests include the search for the muon electric dipole moment, measurement of the muon $g-2$ and muonium laser spectroscopy. These experiments could benefit from a high-quality muon beam at low...
Few-electron molecules are attractive systems for precision spectroscopy because their properties can be calculated with high accuracy by quantum-chemical methods.$^{1,2,3}$ The measurements serve to test theoretical predictions, ideally at the level where their accuracy is limited by the uncertainties of the fundamental constants or by unrecognized physical effects. I will report on precision...
Exotic atoms allow studies in the fields of particle and nuclear physics as well as atomic and molecular phenomena. Inherent to exotic-atom research is a low count rate in the presence of demanding background conditions. Therefore, facilities providing high muon, pion and antiproton fluxes are mandatory in particular for ultimate resolution spectroscopy when using crystal spectrometers. Such...
MuSEUM (Muonium Spectroscopy Experiment Using Microwave) collaboration aims to perform a precise spectroscopy of the ground state muonium hyperfine structure (MuHFS) with high-intensity pulsed muon beam at J-PARC. Our goal is a ten-fold of improvement in a precision of MuHFS compared to the preceding experiment at LAMPF [1]. Muonium is the bound state of a positive muon and an electron. Its...
Positronium and Muonium are excellent systems to test bound-state QED theory to high precision. This has motivated numerous precise experiments aimed at measuring the hyperfine splitting and 1S-2S transition of these atoms.
Currently, there is some disagreement with the most recent bound-state QED calculations for the hyperfine splitting in positronium. Our approach to resolve this, PHySES,...
