Conveners
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- Toshinori Mori (The University of Tokyo)
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- Dieter Ries (Department of Chemistry, Johannes Gutenberg University, Mainz)
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- Marie-Cécile Piro (University of Alberta)
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- Tsutomu Mibe (KEK)
Session: PSI2022- FIPS@CERN Joint Session
- Philipp Schmidt-Wellenburg (PSI - Paul Scherrer Institut)
Session: PSI2022 - FIPS@CERN Joint Session
- Malte Hildebrandt (PSI - Paul Scherrer Institut)
Session: FIPS@CERN - PSI Joint Session
- Georg Bison (Paul Scherrer Institut)
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- Tobias JENKE (Institut Laue-Langevin)
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- Satoshi Mihara (KEK)
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- Michael Jentschel (Institut Laue-Langevin)
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- Kenji Mishima (KEK)
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- Claude Amsler
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- Torsten Soldner (Institut Laue Langevin)
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- Sacha Davidson (IN2P3)
Session
- Kazimierz Bodek (Jagiellonian University, Institute of Physics)
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- Aldo Antognini (ETH)
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- Peter Kammel Kammel (University of Washington, Seattle)
At the Paul Scherrer Institut (PSI) muon rates of up several 10$^8$ $\mu^+$/s are available, produced by its 1.4 MW proton accelerator complex HIPA. While these are currently among the highest muon rates available worldwide, projects in the US and Japan are underway that will be able to surpass these intensities by several orders of magnitude.
In order to maintain PSI’s position at the...
The COMET experiment aims at achieving the sensitivity of mu-e coversion search better than 10^-14 in Phase I and better than 10^-16 in Phase II using highly intense pulsed proton beam provided at J-PARC. The COMET experiment plans to start its engineering run in early 2023 followed by physics data acquisition in 2024. In this presentation, we will report the current status and future prospect...
The Mu3e experiment will search for the charged lepton-flavour violation decay of the muon into two positrons and one electron. With a vanishingly small branching ratio in the Standard Model, any observation of this process will be clear evidence for new physics. A first phase of the experiment aiming for a single event sensitivity of one in $2\cdot 10^{15}$ muon decays is currently under...
The baryon asymmetry of the universe points towards CP-violating sources beyond the Standard Model. If these consist of heavy new particles, their effect at low energies can be described by effective field theories. I will describe theoretical challenges and recent progress within this framework for the extraction of bounds on CP violation from neutron EDM searches. In particular, I will...
Electric dipole moments (EDMs) are a convenient low-energy observable with high-energy implications. They induce violations of parity and time-reversal symmetry in atoms and molecules, which lead to experimental signatures that be precisely measured using atomic physics techniques.
I will provide an overview of EDM searches with atoms and molecules, discuss recent developments, and guess at...
The Standard Model is a well-tested and successful theory of particle physics. However, it does not fully explain the lack of anti-matter observed in the universe. A possible mechanism that could explain this is from new sources of CP violation. This could lead to the existence of a permanent electric dipole moment (EDM) in fundamental particles, through beyond Standard Model interactions....
he Nuclear and Particle Physics (NPP) group of the Institut Laue Langevin (ILL) is operating five public instruments providing an international user community competitive and often unique experimental conditions. We operate the PF1B cold neutron facility – the neutron beam with the worldwide highest flux of cold neutrons, including polarization capability and a large, background free...
Despite decades of effort, quantum electrodynamics (QED) is poorly tested in the regime of strong coulomb fields due to a confluence of difficulties linked to experimental limitations in highly-charged ion spectroscopy and nuclear uncertainties. I will present a new paradigm for probing higher-order QED effects using Rydberg states in exotic atoms, where orders of magnitude stronger field...
The muonium atom is a bound state of a positive muon and an electron, and is one of the hydrogen-like atoms which consists purely of leptons. By measuring the muonium hyperfine structure, the muon mass and the magnetic moment ratio of the proton to the muon can be determined. These values are used to determine the experimental value of muon $g-2$, for which a discrepancy of 4.2$\sigma$ between...
I will present our recent measurement of the n=2, Muonium Lamb Shift of 1047.2(2.5) MHz, which comprises an order of magnitude improvement upon the last determinations and matches with theory within one sigma. This allows us to set limits on Lorentz and CPT violation in the muonic sector, as well as on new physics coupled to muons and electrons which could provide an explanation of the muon...
The proton radius puzzle began in 2010 when the CREMA Collaboration released their measurement of the proton radius (Pohl et. al (2010)) from muonic hydrogen spectroscopy: rp=0.84184(67) fm, This was five standard deviations smaller that the accepted CODATA value at that time (0.8768(69) fm), and sparked an enduring and intriguing puzzle. This puzzle has been addressed in repeated electron...
Measurements of the muonic helium atom hyperfine structure (HFS) is a sensitive tool to test three-body atomic system, bound-state quantum electrodynamics (QED) theory, and determine fundamental constants of the negative muon magnetic moment and mass. The world most intense pulsed negative muon beam at J-PARC MUSE gives an opportunity to improve previous measurements and to test further CPT...
Experimental efforts to probe new physics by measuring atomic parity violating transitions in a trapped radium ion require at least $0.2\,\%$ knowledge of the radium nuclear charge radius. An experiment at the Paul Scherrer Institute (PSI), pursued by the muX collaboration, aims to determine for the first time the absolute nuclear charge radii of $\mathrm{^{226}Ra}$ and other radioactive...
The rate of neutron decay can be precisely calculated, using the theory of electroweak interactions, with an uncertainty on the order of 1e-4. Recent measurements using bottled neutrons have achieved uncertainties below 1 s (0.1 %), but other measurements observing neutron decay in flight disagree by 10 s. Attempts to resolve this discrepancy have spawned much experimental effort as well as...
Different methods of measuring the neutron lifetime lead to discrepant results at about 4.5 sigma. These anomalies are maybe related to yet unfixed systematics but they also can be an indication to new physics beyond the Standard Model. In particular, they can be explained by a neutron transformations in dark matter particles, or they could indicate to new non-standard interactions which...
New measurements of the neutron electric dipole moment (nEDM) will place even tighter constraints on theories involving new sources of CP violation beyond the standard model. It is believed these are required in order to explain the predominance of matter over antimatter (baryon asymmetry) in the universe. The nEDM constrains new physics scenarios at the TeV scale and beyond which do not...
The Fermilab Muon g-2 (E989) collaboration has published the most precise measurement of the muon anomalous magnetic moment $a_{\mu}$ with an uncertainty of 460 ppb in 2021 based on the Run 1 (2018) dataset. The new experimental world average of $a_{\mu}$ deviates by 4.2 standard deviations from the Standard Model prediction provided by the Muon g-2 Theory Initiative.
Following Run 1,...
The MEG experiment searches for the μ+ → e+ γ decay and has recently set the most stringent upper limit on its branching ratio B(μ+ → e+ γ) < 4.2 10-13 at 90% C.L., based on the full data sample acquired during 2009-2013 years. It is a factor 30 improvement over the previous limit set by the MEGA experiment (B(μ+ → e+ γ)< 1.2 10-11 at 90% C.L.) and also the strongest bound on any forbidden...
Time and frequency are the most accurately measurable quantities in physics. Some optical atomic clocks reach a relative frequency uncertainty close to 10-18 and allow to search for deviations in the predictions of Einstein’s general relativity, test modern unifying theories and to develop new sensors for gravity and navigation.
In my talk, I will introduce the concepts of optical clocks and...
Neutron decay is the prototype for nuclear beta decay and other semileptonic weak interactions. The value of the neutron lifetime and angular correlation coefficients can be used to determine the weak coupling constants $G_A$, $G_V$, and the CKM matrix element $V_{ud}$. Neutron decay was important in the early universe and the lifetime is needed in theoretical calculations of primordial...
Measurements of the neutron electric dipole moment (EDM) occupy an important place in today's particle physics. A finite value of the neutron EDM would indicate time-reversal symmetry violation, and based on the CPT theorem, also CP violation. Hence, it serves as a sensitive probe for CP violation. The current best upper limit of $1.8\times 10^{-26}\,e\cdot\mathrm{cm}$ (90% C.L.) [1] is...
Hadronic contributions to the anomalous magnetic moment of the muon
Interpretation of the recent experimental result for the anomalous magnetic moment of the muon by the Fermilab E989 experiment (and even more so of future updates with yet increased precision) depends crucially on the accuracy of the Standard-Model prediction, especially control over hadronic corrections. In the talk, I...
High-precision Penning trap mass spectrometry is the most precise technique employed to measure masses of nuclides with half-lives as short as a few ten ms. Currently, there are about a dozen high-precision Penning-trap mass spectrometers located in North America and Europe. The majority of them are part of various Rare Ion Beam (RIB) facilities and aim at measurements of masses of...
The LUXE experiment (Laser Und XFEL Experiment) is an experiment in planning at DESY, Hamburg, using the electron beam of the European XFEL. LUXE is intended to study collisions between a high-intensity optical laser pulse and 16.5 GeV electrons from the XFEL electron beam, as well as collisions between the laser pulse and high-energy secondary photons. This will elucidate quantum...
Despite the immense success of the Standard Model (SM), it is well known to be incomplete in describing Nature. Most obviously it is not incorporating gravity, and also falling short in explaining cosmological observations like the baryon asymmetry of the Universe, or the nature of dark matter and dark energy. Recent tensions concerning lepton universality are also persistent in the latest...
In this talk, I will discuss light muonic atoms, with a focus on the theory of two-photon-exchange corrections in muonic hydrogen and deuterium. In addition, I will give a summary of the satellite workshop "Proton structure in and out of muonic hydrogen — the ground-state hyperfine splitting”.
The electric dipole moment of the neutron (nEDM) is exceedingly small in standard model of particle physics. However, beyond standard model theories allow for larger values of the nEDM, possibly within the reach of upcoming experiments. This talk will present an overview and status of the nEDM experiment under development at the Los Alamos National Laboratory (LANL) ultracold neutron source...
Over the last decade, measurements of both b→sl+l- and b→clν decays have consistently shown tensions with Standard Model predictions. These tensions are referred to collectively as the flavour or B anomalies. Key drivers of the flavour anomalies include measurements of Lepton Flavour Universality and of the angular distributions of b→sl+ l-decays. This talk will give an overview of the...
The NA62 experiment at CERN collected the world’s largest data set of charged kaon decays in 2016-2018, leading to the first measurement of the Branching Fraction of the ultra-rare $K^+ –> \pi^+ \nu \nu$ decay. The $K^+→\pi^+\nu\bar{\nu}$ decay was observed with a significance of 3.4$\sigma$, based on 20 candidate events. This measurement also sets limits on BR($K^+→\pi^+X$), where X is a...
An experimental apparatus dedicated to search for the permanent electric dipole moment (EDM) of laser cooled francium atoms has been constructed at RIKEN Nishina Center, Japan. In this talk, the principle of the EDM measurement using francium atoms and the experimental status using the newly built apparatus will be presented.
Neutron and nuclear beta decay correlation coefficients are sensitive to the exotic scalar and tensor interactions that are not included in the Standard Model (SM). The experiment BRAND will measure simultaneously seven neutron correlation coefficients: H, L, N, R, S, U and V that depend on the transverse electron polarization – a quantity which vanishes in the SM. Five of these...
The new g-2 measurement suggests new physics in the anomalous magnetic moment of the muon. While this is related to real part of the corresponding Wilson coefficient, the imaginary part gives rise to an electric dipole moment. In this talk, I show that in models with heavy new physics (i.e. realized above the EW scale) one naturally expect a sizable muon EDM within the reach of the planned PSI...
The J-PARC muon g-2/EDM experiment aims to measure g-2 and EDM of muon by using a reaccelerated thermal muon beam and a compact muon storage magnet at J-PARC MLF muon facility. A new surface muon beamline (H-line) has been partially constructed. The first beam was delivered in January, 2022. Remaining parts of construction are in progress. In this talk, status of the experimental preparation...
The goal of MuSun is a first precise measurement of a weak process in the 2-nucleon (2N) system. These reactions include muon capture on the deuteron, μ + d → n + n + ν, together with two astrophysics reactions of fundamental importance, solar pp fusion and νd reactions. The above interactions involve the same, but poorly known axial-vector coupling at a four-nucleon vertex, which also enters...
The ASACUSA collaboration proposed a hyperfine structure (HFS) measurement on a beam of antihydrogen at the antiproton decelerator of CERN to test CPT invariance. Supporting matter experiments are of high relevance in antihydrogen research. They have been performed for the sigma transition ($F$,$M_F$: 1,0 $\rightarrow$ 0,0) of the hydrogen HFS at 1.42 GHz with the noteworthy precision of 2.7...
Two critical questions in particle physics remain unanswered--what is the particle nature of dark matter, and why is there no antimatter in the universe? Searches for neutron oscillations are an essential component of the worldwide program to understand baryon number violation and what comprises dark matter, but are underexplored experimentally. If dark matter is made up of a rich hidden...
The origin of matter and dark matter might be explained by models invoking copies of the Standard Model, e.g. mirror matter, which are sterile under ordinary Standard Model forces. Previous experiments constrained neutron to mirror neutron (n-n’) oscillations by searching for anomalous neutron losses during the storage of ultracold neutrons (UCN). However, the presence of a mirror magnetic...
The instrument PERKEO III was used to measure most precisely the beta asymmetry in neutron decay at the cold neutron beam line PF1b of the ILL, Grenoble. From this measurement, we extract the ratio of nucleon axial-vector and vector couplings. When combined with the neutron lifetime, this provides the CKM matrix element $V_{ud}$ with only a factor two in precision to the combined result from...
The aSPECT collaboration published in 2020 the most precise value on the electron-antineutrino correlation coefficient $a=-0.10407(82)$ of neutron $\beta$-decay. Meanwhile we revised some systematic errors and reanalysed our data including the Fierz interference term $b$. We will present our new value for $a$, which only marginally differs from our previous published result together with the...
Historically, pion and muon decays have provided essential information regarding nature of the electroweak interactions. In modern times, pions and muons are theoretically studied to a high precision within the extremely well understood Standard Model framework. This simplicity permits pion decays to be used as sensitive probes for physics Beyond the Standard Model (BSM). The comparison of...
A next-generation rare pion decay experiment, PIONEER, is motivated by several inconsistencies between Standard Model predictions and data pointing towards the potential violation of lepton flavor universality. PIONEER will measure the charged-pion branching ratio to electrons vs muons (R_pi), a quantity which is very sensitive to a wide variety of new physics effects - including those at...
Astronomical and cosmological observations strongly suggest that most of the matter in our Universe is non-luminous and made of an unknown substance called Dark Matter. But, currently, it remains invisible and undetectable directly on Earth and makes it one of the greatest mysteries in particle physics. Even if its direct detection escapes to the scientific community in our time, dark matter...
The evidence of dark matter so far is based only on gravitational effects observed at cosmological and astrophysical level. To explain these effects, many theoretical models suggest other non-gravitational very-weak interactions between dark matter and ordinary matter. To test this hypothesis, different experiments are trying to directly produce dark matter at particle accelerators.
The...
The search for neutrinoless double beta (0$\nu\beta\beta$) decay is considered as the most promising way to prove the Majorana nature of neutrinos as well as to give indication on the mass hierarchy and on the absolute mass scale. The discovery of 0$\nu\beta\beta$ decay would moreover open the way for theories predicting the observed matter anti-matter asymmetry of the Universe being a...
At the institute of nuclear physics in Mainz, the Mainz Energy-Recovery Superconducting Accelerator MESA is currently under construction. The talk will discuss the physics program of this new high-intensity facility. The polarized extracted beam will be used for parity-violation experiments with the P2 setup, in particular a precision measurement of the weak mixing angle sin$^2 \theta_W$ in...
The current best estimate for the universe’s matter content consists of 84% dark matter, and the search for its composition remains of great interest. One possible candidate is a so-far undetected ultra-low-mass axion. Various astronomical observations and laboratory experiments constrain the axion mass and its interaction strength in the allowed phase space. In this talk, we report on a...
With the Standard Model (SM) of particle physics undisputedly established and well-tested nevertheless a number of major open questions in modern physics remain. These include the observed asymmetric abundances of matter and antimatter in our known universe after baryogenesis. The NNBAR experiment [1] was proposed to search for baryon number violation (BNV) due to conversion of a neutron (n)...
While neutrino oscillations disprove massless neutrinos, decay kinematics give access to their absolute mass value. Using high-precision tritium beta-decay spectroscopy, the KATRIN experiment places the current best limit on the effective electron anti-neutrino mass at 0.8 eV (90% CL). New operational conditions for an improved signal-to-background ratio, the reduction of systematic...
Cyclotron radiation emission spectroscopy (CRES) is a new avenue towards high-precision measurements of nuclear ?-decay spectra. High energy resolution and intrinsic low background have been demonstrated for CRES. As frequency-based technology CRES has an independent set of systematic uncertainty contributions in comparison to most classical electron spectroscopy techniques. Combined with an...
S. Ulmer$^1$, C. Smorra$^{1,2}$, F. Abbass$^2$, K. Blaum$^3$, M. Bohman$^{1,3}$, M. Borchert1,$^4$, J. A. Devlin$^{1,5}$, S. R. Erlewein$^{1,3,5}$, M. Fleck$^{1,6}$, P. Geissler$^{1,5}, J. I. Jaeger$^{1,3}, B. M. Latacz$^1$, D. Popper$^2$, G. Umbrazunas$^{1,7}$, M. Wiesinger$^{1,3}$, C. Will$^3$, E. J. Wursten$^{1,3}$, Y. Matsuda$^6$, C. Ospelkaus$^4$, W. Quint$^7$, A. Soter$^8$, J....
At CERN, we have recently become able to study atoms of antihydrogen - the antimatter equivalent of hydrogen. The question to be addressed is fundamental and profound: “Do matter and antimatter obey the same laws of physics?” The Standard Model requires that hydrogen and antihydrogen have the same spectrum. The possibility of applying the precision measurement techniques of atomic physics to...
