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...
"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...
