124048289
A search for deeply bound kaonic nuclear states at J‐PARC
J‐PARC E15 experiment aims to search for the lightest kaonic nuclei, namely K−pp bound states, using in‐flight (K−, n) reactions. The advantage of this experiment is to perform exclusive measurement by missing mass study using the primary neutrons and invariant mass spectroscopy via such decay as K−pp→Λp→pπ−p, simultaneously. In this report, an overview of this experiment and the current status are presented.
124815658
Measure of the spatial size for the monopole excitation in proton scattering
122600834
Muon catalyzed fusion experiments on muonic deuterium atom deceleration in thin solid deuterium films
Abstract Muon catalyzed fusion was investigated in a series of thin solid deuterium films by detecting protons from dd fusion. Two different contributions to the total fusion yield resulting from dμ atoms emitted from a primary hydrogen layer and from incident muons directly stopped in the deuterium film itself were observed. The thickness dependence of the fusion yield suggested the importance of molecular effects in dμ elastic scattering in D 2 .
124123633
SEARCH FOR LORENTZ AND CPT VIOLATION EFFECTS IN MUON SPIN PRECESSION
117791711
Radioactive Muonic Atom Studies with Intense Muon Beams
New intense muon beams with flux several orders of magnitude higher than at present muon facilities would allow many novel experimental studies that were until now statistically not feasible. The investigation of the nuclear properties of short‐lived nuclei using muonic atom spectroscopy would become possible. In this paper, the recent progress of a feasibility study at RIKEN‐RAL muon facility using the cold hydrogen film method to produce radioactive muonic atoms is being reported. The first experimental results have just been obtained with stable argon ions implanted in solid deuterium films.
121882195
Discovery of the repulsive energy shift of the kaonic hydrogen 1s state
Abstract The aim in this manuscript is to clarify the progress in understanding the nature of the K ¯ N interaction at the lowest energy, given by the recent kaonic hydrogen X-ray experiment at KEK [1]. We have observed a clear spectrum showing the kaonic hydrogen K α line, for the first time. The analysis gives the repulsive energy shift to be Δ E (1 s ) = −323 ± 63(statistical) ± 11 (systematic) eV and the energy width to be Λ(1 s ) = 407 ± 208 ± 100 eV. This result is consistent with analyses of the previous low-energy scattering data and resolves the long-standing kaonic hydrogen puzzle.
119756253
R&D status of a large-aperture hybrid avalanche photo-detector
This paper reports on the R&D status of a large-aperture Hybrid Avalanche Photo-Detector (HAPD). We have developed a 13-inch aperture HAPD and its readout system. The HAPD is a photo-detector expected to replace the photomultiplier tube (PMT) in next-generation imaging water Cherenkov detectors such as Hyper Kamiokande. We will present the recent progress made in readout system development. The readout system involves a fast sampling device. The sampling depth (number of cells) has been extended to 256 from 64 in order to measure longer waveform length. The variation in AC gain is now fixed and the input analog bandwidth improved.
121035915
QUARKONIUM AT FINITE TEMPERATURE
We study quarkonium at finite temperature by using a hadron string model. It is shown that as the temperature is increased, the mass of the quarkonium decreases and the slope of the Regge trajectory is changed.
55994477
BEAM BACKGROUND AND MDI DESIGN FOR SUPERKEKB/BELLE-II
The Belle experiment, operated at the asymmetric electron-positron collider KEKB, had accumulated a data sample with an integrated luminosity of more than 1 ab −1 before the shutdown in June 2010. We have started upgrading both the accelerator and the detector, SuperKEKB and Belle-II, to achieve the target luminosity of 8 × 10 35 cm −2 s −1 . With the increased luminosity, the beam background will be severe. The development of MachineDetector Interface (MDI) design is crucial to cope with the increased background and protect Belle-II detector. We will present the estimation of impact from each beam background sources at SuperKEKB and our countermeasures for them, such as collimators to stop Touschek-scattered beam particles, Tungsten shield to protect inner detectors from shower particles, and dedicated beam pipe design around interaction point to stop synchrotron radiation, etc.
6081502
Mass spectra and decay widths of hadrons in the relativistic string model
A relativistic string model for hadrons is presented. The center-of-mass motion is separated correctly. The vibrational and rotational motions of the string are solved by using the WKB approximation. Moreover, their decay widths are calculated by taking into account the pair creation of quarks inside the string. Both the mass spectra and the decay widths are reproduced fairly well in comparison with experimental data.
123251544
Thermodynamic Properties of Color Superconducting Quark Matter
Thermodynamics for color superconducting quark matter is investigated on the basis of the one-gluon-exchange model. Thermodynamic quantities are calculated by using a mean field (BCS) approximation. It is shown that there exists a phase transition of second order between the superconducting phase and normal phase. The pressure and density become larger in the superconducting phase. The specific heat and compressibility have a discontinuity at the critical temperature.