133597393
Search for the deeply bound $K^-pp$ state via the $^3$He($K^-,n)$ reaction at $p_{K^-}$=1 GeV/$c$
An experiment to search for the Kpp bound state was performed via the in-flight He(K, n) reaction at θ n = 0 ◦ using 5.3 × 10 kaons at 1 GeV/c at the J-PARC hadron experimental facility. In the neutron missing-mass spectrum, no significant peak was observed in the region corresponding to Kpp binding energy larger than 80 MeV, where a bump structure was reported in the Λp final state in different reactions. Mass-dependent upper limits of the production cross section for the state isotropically decaying into Λp were determined at 95% confidence level to be (30–180), (70–250), and (100–270) μb/sr, for the natural widths of 20, 60, and 100 MeV, respectively.
124815658
Measure of the spatial size for the monopole excitation in proton scattering
124123633
SEARCH FOR LORENTZ AND CPT VIOLATION EFFECTS IN MUON SPIN PRECESSION
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.
122137776
A Model for Shock Waves in High Energy Heavy Ion Collisions
119429294
Shear viscosity of the quark matter
We discuss shear viscosity of the quark matter by using the Kubo formula and the Nambu–Jona–Lasinio model. It is shown that the leading term of 1/N expansion for the shear viscosity is equivalent to the quasi-particle random phase approximation. Using this approximation, we obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. If we assume the Breit–Wigner type for the spectral function, the shear viscosity is evaluated as a function of the imaginary part of the quark self-energy, which is related to the mean-free path of the quark. It is pointed out that the quark matter seems to be a perfect liquid for the mean free path <2 fm.
25502171
Rotating Bag Model for Hadrons
The MIT bag model!) has been quite successful in reproducing the observed masses and other static properties of the low-lying hadrons. It is very important to discuss whether or not excited states of the hadrons (resonances) can be explained in the framework of the bag model. A number of excited states have been described successfully by considering collective excitations of the bag.) In particular, Johnson and Thorn) investigated a series of excited states known as the Regge trajectory by using the rotating bag model. They assumed that the rotating bag has stringlike shape with two ends by the centrifugal force and the transverse length is negligible compared with its longitudinal one. From this onedimensional bag model, they succeeded in reproducing the experimental value of the Regge slope very well. Furthermore it was showt: by Wakimaru and one of the present authors (M. I.) that this simple model can explain not only the Regge slope but also the energy spectra of the trajectories.) On the other hand, Eguchi and Migdal et aJ.5) also discussed the excited states by using their string models 'which are independent of the bag model. Any string model which has been proposed is based on the assumption that the shape is stringlike or one-dimensional. Is the assumption of the stringlike shape, however, surely true? section of the stringlike bag, which we call tube, can be given by
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.
122800760
Phase Transition of Quark Matter at High Density.