18985470
A search for deeply bound kaonic nuclear states
Abstract We have measured proton and neutron energy spectra by means of time-of-flight (TOF) from 4He( K stopped − , p / n ) reactions (KEK PS E471 experiment). In the proton spectrum, a clear mono-energetic peak was observed under semi-inclusive condition, which was assigned to the formation of a strange tribaryon S0(3115) with isospin T = 1 . The mass and width of the state were deduced to be 3117.7 −2.0 +3.8 ( syst . ) ± 0.9 ( stat . ) MeV / c 2 and 21.6 MeV / c 2 , respectively, and its main decay mode was Σ N N . In the neutron spectrum, a mono-energetic peak was found as the result of a detailed analysis, which was assigned to the formation of another kind of strange tribaryon S+(3140). The mass and width of the state were deduced to be 3140.5 −0.8 +3.0 ( syst . ) ± 2.3 ( stat . ) MeV / c 2 and 21.6 MeV / c 2 , respectively, and its main decay mode was Σ ± N N . The isospin of the state is assigned to be 0. The results are compared with recent theoretical calculations.
124815658
Measure of the spatial size for the monopole excitation in proton scattering
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.
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 .
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.
124123633
SEARCH FOR LORENTZ AND CPT VIOLATION EFFECTS IN MUON SPIN PRECESSION
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.
123071679
Regge trajectories of baryons in the MIT bag model
Abstract We investigate Regge trajectories of baryons in the MIT bag model. It is shown that the energy spectra shown by the trajectories can be described fairly well by the stringlike solutions of the bag model. In particular, three strings with one junction and three ends can explain the delta trajectory better than one string with two ends. The three ends occupied by each quark are assumed to be an equilateral triangle configuration in our calculations.
120273120
A Modified Glauber Approximation for High-Energy Heavy Ion Collision. II Effect of the Internal Excitation of the Projectile Nucleus
55054869
CONSTRUCTION AND COMMISSIONING OF EVENT TIMING SYSTEM AT SUPERKEKB
KEK linac upgrades its Event Timing System for the coming SuperKEKB project. The Event Timing System is required more complicated injection control. The damping ring is used to suppress emittance in the positron injection. The number of top-up filling rings is increased. We installed the new configuration of Event modules at Main Trigger Station for satisfying the new requirements. Besides, the upgrade of software, rearrange of optical wiring, and feasibility study are performed as the upgrade work. We conclude the new Event Timing System becomes valid. The commissioning of beamline and operation for injections with new system will be performed soon.
56442734
Effect of Soft Mode on Shear Viscosity of Quark Matter
We calculate the shear viscosity of quark matter at finite temperature and density. If we assume that the quark interacts with the soft mode, which is a collective mode of a quark-antiquark pair, the self-energy of the quark is calculated by quasi-particle random phase approximation. It is shown that its imaginary part is large and its mean free path is short. With the use of the Kubo formula, the shear viscosity of quark matter decreases. The Reynolds number of quark matter is estimated to be about 10. As temperature increases, shear viscosity increases gradually for T> 200 MeV. Moreover it is shown that the shear viscosity also increases with the chemical potential for μ> 200 MeV.