The neutron lifetime is a fundamental parameter in nuclear and particle physics, with implications for Big Bang nucleosynthesis, weak interaction studies, and searches for new physics beyond the Standard Model. Over the past decades, increasingly precise experiments have been performed using two main approaches: the “bottle” method, which traps ultracold neutrons, and the “beam” method, which...
The ``neutron lifetime puzzle'' arises from the discrepancy between neutron lifetime measurements obtained using the beam method, which measures decay products, and the bottle method, which measures the disappearance of neutrons. To resolve this puzzle, we conducted an experiment using a pulsed cold neutron beam at J-PARC. In this experiment, the neutron lifetime is determined from the ratio...
The unitarity of the CKM quark mixing matrix can be tested by measuring the unitarity sum of the f irst row, which requires precision extraction of the first element (V$_\mathrm{ud}$). V$_\mathrm{ud}$ can be measured by combining measurement of the neutron lifetime with the axial-vector weak coupling constant. The Nab experiment, located at the Spallation Neutron Source at Oak Ridge National...
The neutron represents a versatile tool in the realm of fundamental particle physics. It is used to perform precision physics measurements at low energies with the goal to search for signals beyond the Standard Model of particle physics. In this respect, the neutron Electric Dipole Moment (EDM) has attracted interest as a promising channel for finding new physics since decades. The existence...
Recent progress of the TRIUMF Ultra Cold Advanced Neutron Source and EDM Experiment The TUCAN collaboration is commissioning a world-leading ultracold neutron (UCN) source at TRIUMF, capable of production rates up to 1.6$\times 10^7$ UCN/s once completed. Spallation neutrons are cooled in room temperature heavy water and 20K liquid deuterium, followed by UCN production in a spherical volume of...
The search for a permanent electric dipole moment of the neutron (nEDM) has been going on for over 60 years and is still a hot topic with various ongoing efforts worldwide. I will present the status of the work of the nEDM collaboration at PSI. The current best limit resulted from the previous measurement at PSI. The nEDM collaboration has developed a new apparatus 'n2EDM', which is being...
The FNAL muon g-2 experiment has measured the anomalous magnetic moment of the muon with an unprecedented precision of 127 ppb [1]. In parallel, significant theoretical efforts are underway to predict the Standard Model (SM) value of muon g-2 with comparable precision [2]. A new experiment aiming to simultaneously measure the muon g-2 and electric dipole moment (EDM), using the world’s first...
Electric dipole moments (EDM) of fundamental particles inherently violate the combined symmetry of charge-conjugation and parity inversion (CP) . At PSI we plan to measure the EDM of the muon using the frozen-spin technique within a compact storage trap. This method exploits the high effective electric field, E = 165 MV/m, experienced in the muon’s rest frame with a momentum of about 23 MeV/c...
Studies of fundamental symmetries violations in atoms and molecules provide some of the most confronting tests of the Standard Model and sensitive searches for new physics beyond. In this talk, I will focus on atomic parity violation and give the current status and key challenges of the theory. I will also discuss how atoms may be used to deduce improved nuclear physics properties, essential...
The flavor diagonal CP violation of elementary particle physics contributes to the atomic, nuclear, and nucleon electric dipole moments (EDMs), T-violating neutron scattering, and to the angular correlations of beta decay. However, its extraction from experimental data has for long been obstructed by the nonperturbative physics of quantum chromodynamics. Quite recently, there were significant...
Time Reversal Invariance Violating (TRIV) effects in neutron transmission through a nuclei target are discussed. We explore the possibility to search TRI violation using important advantages of neutron nuclei interactions: the enhancement of TRIV observables by many orders of magnitude, the measurements of relative effects (TRIV and parity violating ones at the same resonances) with a...
The fundamental parity violating effect caused by the hadronic weak interaction is enhanced by up to 10^6 times in neutron absorption reactions of 139La, 131Xe, 117Sn, and other nuclei. This enhancement can be explained by the mixing between s-wave and p-wave amplitudes of the compound nuclear state (s-p mixing model). Similarly, T-violating effect in the nucleon-nucleon interaction can also...
The GBAR experiment is designed to investigate the weak equivalence principle by measuring the free-fall acceleration of antihydrogen in the Earth gravitational field [1]. The goal is to obtain a precision of 1% in a first phase, later to be improved using quantum reflection on a surface [2]. To achieve this, the first step is to produce sympathetically coolable antihydrogen ions, through two...
In the limit of vanishing quark masses, QCD exhibits a chiral symmetry. This symmetry is not only broken explicitly by the finite physical quark masses, but is also assumed to be broken spontaneously. Chiral symmetry and its breaking form the basis of a series of effective field theories used to describe the low-energy interactions between hadrons and their coupling to external fields....
Charged lepton flavor violation (cLFV) is a clear signature of physics beyond the Standard Model (SM). While cLFV is not expected to be observed in the SM, many new physics models predict reachable branching fractions of cLFV decays in the current and future experiments. The Belle II experiment, located at the SuperKEKB asymmetric-energy e+e− collider, is a "tau factory" and is good place to...
The theory of elementary particle physics, the Standard Model (SM), provides a successful description of the basic constituents of matter and the forces acting between them. However, it explains only about 15 % of the total mass in the universe, not accounting for the dark matter postulated in the face of astrophysical and cosmological data. The study of the universe at large shows that our...
Muonium is a pure leptonic binary system consisting of a positive muon and an electron, and its level structure can be calculated with high precision. The Muonium Spectroscopy Experiment Using Microwave (MuSEUM) experiment aims to verify the quantum electromagnetic dynamics theory and determine the positive muon magnetic moment and mass by precise measurements of the ground-state hyperfine...
Microwave spectroscopy of the ground-state hyperfine structure (HFS) of muonic helium atoms is underway at J-PARC Muon Experimental Facility (MUSE) to determine the magnetic moment and mass of the negative muon with high precision. Muonic helium is a hydrogen-like atom composed of a helium atom with one of its two electrons replaced by a negative muon. Its ground-state hyperfine structure,...
It is crucial to explore physics beyond the Standard Model (BSM) because the Standard Model is incomplete in explaining questions that arise from cosmological observations, such as the existence of dark matter and the matter-antimatter asymmetry in our universe. Precise spectroscopy of muonium is a powerful way to search for BSM because of muonium’s simple energy structure. Muonium is a purely...
We present a new rigorous scheme for understanding quark confinement based on the non-perturbative vacuum disordered by some topological defects. We start from the 4-dim. Euclidean Yang- Mills theory and require the conformal equivalence between the 4- dim.Euclidean space and the possible curved spacetimes with some compact dimensions. This requirement forces us to restrict the gauge...
First principles, or ab initio, nuclear theory describes atomic nuclei as systems of nucleons interacting by QCD-based chiral effective field theory (EFT) nucleon-nucleon and three-nucleon forces. In combination with chiral EFT electroweak currents, ab initio nuclear calculations can provide model-independent results with quantifiable uncertainties relevant for tests of fundamental symmetries i...
A low energy particle confined by a horizontal reflective surface and gravity settles in gravitationally bound quantum states. These gravitational quantum states (GQS) were so far only observed with neutrons [1,2]. However, the existence of GQS is predicted also for atoms. The GRASIAN collaboration pursues the first observation of GQS of atoms, using a cryogenic hydrogen beam. This endeavor...
The coherent scattering length (b_c) is a key parameter for neutron experiments. In addition, the b_c for some nuclei have important physical significance. The b_c is measured by several methods, including cross-section measurements and diffraction, and is mainly measured using a neutron interferometer(NI). However, the sensitivity of conventional NI, which is made of Si crystal, has...
The COW experiment conducted in 1974 was the first to observe the gravitational interaction of neutrons as quantum particles. In this experiment, the phase shift was measured between neutron waves traveling along two paths at different heights in an interferometer, reflecting the difference in gravitational potential. Precise measurements of gravitational effects on neutrons can test the...
Francium (Fr), the heaviest alkali element, is predicted to exhibit the largest enhancement factor of electron electric dipole moment (EDM) among alkali atoms, making it a promising candidate for probing physics beyond the standard model. To realize a high-precision EDM measurement with Fr, laser cooling and quantum control techniques are typically employed. In our experiment, we aim to trap...
Neutron-antineutron oscillations, which violate both B and B-L, have attracted attention in the context of baryogenesis to explain the matter-dominated universe. In searches for the oscillations, the antineutron-nucleus scattering length is one of the important parameters. We plan to perform scattering experiments using low-energy antineutron beams at the CERN AD.
The electron’s electric dipole moment (EDM) is a parameter that violates CP symmetry assuming the CPT invariance. Measuring the EDM provides constraints on the theories beyond the Standard Model of particle physics. Francium (Fr) is expected to exhibit the largest enhancement factor for the electron EDM among all alkali atoms. Because Fr has no stable isotope, we adopted Fr-221 produced via...
In order to measure the electron’s electric dipole moment (eEDM), a sufficient number of atoms must be trapped to reduce statistical uncertainty. In particular, to realize it, stabilizing laser frequency is required.
In this experiment, saturated absorption spectroscopy (SAS) was employed with
techniques of frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS) to...
The electric dipole moment (EDM) has been investigated as a highly sensitive probe for physics beyond the standard model. The EDM of francium (Fr) has attracted attention as a target for measurements of electron’s EDM because the enhancement factor of electron’s EDM for Fr is 799 [1] and laser cooling and trapping of Fr elongates the interacting time with electric fields.
To evaluate the...
"The thorium-229 nucleus possesses a first excited isomeric state with an excitation energy of 8.36 eV, which is extremely low for an atomic nucleus.
In 2024, laser excitation was achieved using a vacuum ultraviolet (VUV) laser[1][2][3], raising expectations for applications such as high-precision frequency standards.
We performed comprehensive spectroscopy experiments of 229Th-doped CaF2...
We are developing a device to trap muons in a Penning trap at J-PARC. Recently, we succeeded in trapping negative muons in vacuum using a pulsed electric field and a static magnetic field. Although a negative muon stopped in matter is captured by its atomic nucleus and its lifetime gets shorter than in vacuum, we can measure the lifetime of the negative muon directly using our muon trap...
Neutrinos undergoing stochastic perturbations as they propagate may experience decoherence which leads to a damping in the neutrino oscillation probability over distance. Such perturbations may result from quantum gravitational effects such as neutrino-virtual black hole interaction scenarios. My project is about investigating the resulting signals in DUNE and T2K and test the sensitivity of...
Coherent amplification is useful to detect very weak signals, like signals from axions, dark photons, etc. Because its signal intensity is proportional to the square of the atoms inside the system. Ion-doped crystal is a very good material for coherent amplification due to its dense number of atoms inside the crystal. In order to detect such a weak signal, one must generate a coherence between...
The thorium-229 nucleus has an exceptionally low first excited isomeric state at around 8 eV. As it can be excited by laser light, it is expected to be used in the development of nuclear clocks. In particular, solid-state nuclear clocks employing crystals doped with thorium-229 are anticipated to enable compact and outstandingly stable time standards as they can simultaneously excite a large...
"The existence of a permanent electric dipole moment of the electron (eEDM) would violate time-reversal symmetry and suggest new physics beyond the Standard Model.
Recently, polar molecules have been widely used in eEDM research because they generate strong internal effective electric fields and can offer quantum states that help suppress systematic errors.
In particular, beam-based...
Deceleration of heavy polar molecules is one of the critical steps toward future searches for the electric dipole moment (EDM) using molecules [1], enabling extended coherence times or efficient trap loading. Among various techniques developed for molecular slowing, such as laser slowing [2], Stark deceleration [3,4], and Zeeman Sisyphus methods [5], centrifuge deceleration [6] offers distinct...
"The ALPHA (Antihydrogen Laser PHysics Apparatus) experiment uses magnetically trapped antihydrogen to test fundamental matter–antimatter symmetries. As the simplest anti-atom, antihydrogen is a promising candidate for testing CPT symmetry in an atomic system and the Weak Equivalence Principle (WEP) with antimatter. ALPHA has already achieved major milestones, including the first observation...
Precision spectroscopy of exotic atoms, such as muonium and antihydrogen, is a powerful method for testing the Standard Model of particle physics and searching for new physics beyond it. For example, measurements of the muonium hyperfine structure provide the most stringent tests of bound-state quantum electrodynamics (QED), while spectroscopy of antihydrogen allows for high-precision tests of...
A significant enhancement of parity violation in the nucleon-nucleon interaction has been observed in compound nuclei formed when medium-mass nuclei such as 139La and 131Xe capture neutrons at specific resonance energies. This enhancement is considered to result from the mixing of s and p wave neutron amplitudes. Theoretically, similar mechanisms are also expected to greatly amplify...
Francium (Fr) is expected to exhibit the largest atomic electric dipole moment (EDM) among alkali atoms, making it an ideal candidate for probing physics beyond the standard model. In particular, 221Fr is of interest due to its potential for continuous extraction from 225Ac and its enhanced sensitivity to quark EDMs through nuclear octupole deformation. To achieve high-precision EDM...
"The ultra-slow muon (USM), developed for the J-PARC Muon g-2/EDM experiment, is produced through the ionization of muonium at room temperature using a combination of 122 nm and 355 nm laser—a process known as muon cooling. The first beam test employing this laser setup is scheduled at the end of 2025. Despite its crucial role in determining USM yield, the laser system has several challenges...
The NOPTREX collaboration aims to search for time-reversal symmetry violation (T-violation) beyond the Standard Model using compound nuclear reactions. For a high-sensitivity T-violation search, the spins of polarized neutrons and polarized nuclear targets must be aligned perpendicularly. However, transporting neutron spin orientation is technically challenging. As a Phase-1 experiment, we...
"The NOPTREX collaboration is planning to explore time-reversal invariance violation (T-violation) in neutron compound nuclear resonances using a polarized $^{139}$La target. For this purpose, we are developing a polarized target system based on dynamic nuclear polarization (DNP), in which a single crystal of LaAlO$_3$ doped with a small amount of Nd$^{3+}$ ions is used as a target material....
"The NOPTREX collaboration is planning to search for time-reversal symmetry violation(T-violation) in nucleon-nucleon interaction at J-PARC. The search for T-violation involves measuring the T-odd cross-section between polarized neutrons and polarized nuclei. For highly-sensitive T-violation search, we require neutron detectors capable of operating under high flux conditions without...
Spectroscopy of hadronic atoms, where a negatively charged hadron such as π −, K−, or ̄p replaces an electron, offers a unique way to study the strong interaction. Among them, x-ray spectroscopy of antiprotonic atoms provides in-formation on antinucleon–nucleus interactions at low energy. Although a model exists based on global fits to data acquired up to the 1980s, it is limited by...
The dual superconducting picture is one of the most promising scenario for quark confinement, where magnetic monopoles play a dominant role for confinement. Indeed, we have shown numerical evidence for the magnetic monopole dominance in the string tension on the lattice in gauge invariant way based on the the gauge-covariant decomposition due originally to Cho-Duan-Ge-Shabanov and...
The ASACUSA-Cusp collaboration intends to perform precision microwave spectroscopy of the antihydrogen ground-state hyperfine splitting to compare with analogous measurements in hydrogen [1]. This comparison can place limits on CPT violation and probes the matter-antimatter asymmetry. The beam needs to be spin polarised in the ground-state, with a velocity of <1500 m/s, to be compatible with...
Whispering gallery states (WGS) of neutrons and cold atoms, as well as their interferences, are a very powerful tool to probe surface potentials in a curved wave guide. They form in slow particle beams that are confined by the quasi-centrifugal potential generated by the curvature of the wave guide, and the surface interaction exerted from the atoms of the wave guide on the particle beam....
The DeeMe experiment is planned at J-PARC MLF H-Line.
The experiment aims to search for the muon to electron conversion in the nuclear field, which is one of the charged lepton flavor violating processes that are forbidden in the Standard Model and expected to be highly sensitive to search for new physics.
The DeeMe experiment will be the first search with using muonic carbon atoms.
We aim...
The MuSIC beamline at the Research Center for Nuclear Physics (RCNP), Osaka University, provides a high-intensity continuous muon beam using proton beam (392MeV, 1.1 μA). Pions and muons generated in the graphite target are efficiently captured by the large solid angle superconducting solenoid magnet and are transported to the downstream[1] . At the experimental port located at the end of the...
We conducted a non-destructive elemental depth analysis of a Roman silver coin excavated from the Tell Mishrifat Hajj Ali Issa, located in northern Syria, housed at the Ancient Orient Museum, using the negative muon beam at the Muon Science Laboratory (MSL), J-PARC. The developed detection system measured muonic X-rays induced at various implantation depths of negative muons, enabling...
High-efficiency muonium production targets are a key element in research utilizing ultra-slow muon (USM) generation, such as the g-2/EDM experiment and transmission muon microscope. In particular, applications like transmission muon microscope require not only small-emittance sources, traditionally realized with planar silica aerogels, but also spatial convergence of USM beams. To address this...
To advance the development of the Lyman-α light source for generating ultra-slow muons at J-PARC, as well as for spectroscopy and experiments involving muonium, hydrogen, and antihydrogen, it is essential to control not only spectral stability but also linewidth. In previous ultraslow muon experiments, the Lyman-α wavelength was tuned to the muonium 1s-2p resonance transition, and the spectral...
The anomalous magnetic moment (g−2) and the electric dipole moment (EDM) of the muon provide sensitive probes of physics beyond the Standard Model. While the muon g−2 shows a potential discrepancy between theory and experiment, the EDM is predicted to be vanishingly small, making any observation a clear sign of new physics.
The J-PARC muon g−2/EDM experiment aims to provide an independent g−2...
The angular distribution of individual γ-transitions from neutron-induced compound nuclear state via (n, γ) reaction in p-wave resonances of 139La[1], 131Xe[2], 117Sn[3] and other nuclei has been studied using the ANNRI HpGe detector array at J-PARC BL-04 with precise γresolution. Such angular distributions in p-wave resonances may arise from the mixing between s- and p-wave amplitudes[4].
An...
Positronium (Ps), a purely leptonic bound state of an electron and a positron, offers a unique platform for testing fundamental physics, including gravity on antiparticles [1] and a gamma-ray laser [2]. Achieving Bose-Einstein condensation (Ps-BEC) would be a breakthrough, requiring ultracold temperatures (approximately 10 K) and a dense state (around 10¹⁸ cm⁻³) Ps within its short lifetime of...
This talk reports the result of the search for the decay \mu+->e+\gamma undertaken at the Paul Scherrer Institut in Switzerland with the MEG II experiment using the data collected in the 2021- 2022 physics runs. The sensitivity of this search is 2.2x10-13, a factor of 2.4 better than that of the full MEG dataset and obtained in a data taking period of about one fourth that of MEG, thanks to...
The 229mTh isomeric state has the lowest known energy for a nuclear transition and is a candidate for a clock disciplined by an atomic nucleus. After demonstrating the absolute transition frequency measurement, we now move on to characterizing its environmental sensitivity as a clock, and present preliminary results regarding the effect of resonant microwaves. A clock based on this transition...
The nuclear transition between the nuclear ground state and the isomer of thorium-229 offers a unique opportunity for direct laser spectroscopy of the atomic nucleus. One of the applications is a high-accuracy nuclear clock based on the resonance frequency of this nuclear transition. We developed an ion trap for triply charged thorium-229 obtained as recoil ions from the -decay of...
We propose new axion models in which the Peccei–Quinn (PQ) symmetry is identified with baryon and/or lepton number symmetries. By extending the KSVZ axion model with higher- dimensional operators, we develop a general method to fix the baryon and lepton numbers of new scalar fields. This framework naturally predicts distinctive baryon-number violating processes such as nucleon decays,...
In the early universe, matter and anti-matter, produced equally in high-temperature density, are assumed to annihilate one another. However, the current universe is dominated by only matter. The “mystery of matter-dominated universe” is one of the big problems in particle physics and cosmology, and neutrinos are expected to be a key to the solution. More than 80 years ago, the physicist Ettore...
The European Spallation Source (ESS), currently under construction in Lund, Sweden, will become the world’s most powerful neutron research facility. The proposed NNBAR experiment aims to perform the first search in over three decades for free neutron–antineutron oscillations. Such a transformation would constitute direct evidence of baryon number violation, a phenomenon anticipated by several...
The search for the fundamental physics using atoms and molecules have been widely investigated [1]. The discovery of the electron’s electric dipole moment (EDM) sheds light on new physics beyond the standard model. The upper limit of EDM has been reported [2]. We propose a novel experimental technique to measure the electron EDM using ultracold Fr atoms based on the combined principles of...
Molecules containing radioactive nuclei are being pursued for a wide range of applications, from fundamental symmetries to nuclear astrophysics. However, their study is made challenging by the combination of limited quantity and the difficulty of working with even the simplest molecules. Here I will describe the production and spectroscopy of cold, stopped 226RaOH, 226RaOD, and 226RaF in a...
Electric dipole moments (EDMs) play a central role in searches for CP violation beyond the Standard Model.
This talk reviews activities at the COoler SYnchrotron COSY at Forschungszentrum Juelich in Germany.
A series of milestones in the preparation for electric dipole measurements
of charged hadrons in storage rings have been achieved in recent years at COSY.
These include the...
Two new tabletop measurements promise to each increase by an order of magnitude the sensitivity for testing the SM and for probing for BSM (beyond the SM). For the electron magnetic moment, a one-electron relativistic quantum cyclotron already provides the most precise measurement — the most precisely measured property of any elementary particle — to test the most precise prediction of the SM....
The standard model predicts a value for the electron’s electric dipole moment (eEDM, d$_\textrm{e}$), d$_\textrm{e}$ ~ 10$^{-35}$ e cm [1], far smaller than what is predicted by theories beyond the standard model, typically d$_\textrm{e}$ ≈ 10$^{-31}$ – 10$^{-24}$ e cm. To date, the current experimental upper limit is set at d$_\textrm{e}$ < 4.1 x 10$^{-30}$ e cm [2]. Further improvements in...
An e ective theory of charge lepton flavor violation (CLFV) was recently developed, yielding a complete set of nucleon-level operators through linear order in the nucleon and muon velocities. The embedding of this operator basis in a nucleus then determines what can and cannot be learned about CLFV from muon-to-electron conversion. Due to several technical tricks introduced, we were able to...
The COMET experiment at J-PARC aims to search for the coherent, neutrinoless conversion of a muon into an electron in the field of an aluminium nucleus. This process violates charged lepton flavor conservation and is forbidden in the Standard Model, so its observation would be a clear indication of new physics. COMET targets an ultimate single-event sensitivity of $10^{-17}$, improving the...
Neutrino oscillations have shown that lepton flavor is not a conserved quantity. Charged lepton flavor violation (CLFV) is suppressed by the small neutrino masses well below what is experimentally observable, while new physics models predict higher rates of CLFV. The CLFV μ− → e− conversion process is sensitive to a wide range of new physics models. The upcoming Mu2e experiment at FNAL will...
n this contribution I will review the experimental efforts currently operated at the antimatter factory of CERN to test the fundamental charge, parity, time reversal invariance and other fundamental symmetries using antiprotons, antiprotonic atoms, and antihydrogen. The talk will review several world-class precision spectroscopy results, including proton/antiproton charge-to-mass ratio and...
In modern physics, four fundamental interactions—electromagnetic, strong, weak, and gravitational—are being studied under a unified framework known as the Theory of Everything. Among them, gravity is significantly weaker than the others, which has been known as the hierarchy problem. One proposed solution is the Large Extra Dimension (LED) model, which suggests that additional spatial...
To experimentally make breakthroughs in exploring quantum gravity, searching for the violation of the gravitational inverse square law to probe large extra dimensions predicted by string theories, and the violation of Lorentz symmetry, is attracting significant interest. Recent progress on these fields and their interpretations will be presented in this talk. Especially, the gravitational...
"The P-violating effect in compound nuclear states in medium heavy nuclei is amplified by up to approximately 10^{6} times compared to nucleon-nucleon scattering. This phenomenon is observed when the p-wave resonance lies at the tail of the s-wave resonance. It arises from the mixing of two resonant states with different parity in a compound nuclear state due to weak interactions (s-p mixing...
