103405849
Kaonic Atoms Experimental Studies At Dafne
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
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 .
185755181
The SuperKEKB accelerator status
67846515
A Modified Glauber Approximation and the Formation of Shock Waves in High-Energy Heavy Ion Collisions
Coherent features in high energy heavy ion collisions are investigated from a microscopic viewpoint. A modified Glauber approximation which enables us to include the slowing down of the relative motion between the centers of masses of both nuclei is presented. The generation of the shock wave is shown to be suppressed by this slowing down effect. As an application inclusive nucleon spectra and the two-particle correlation are calculated in the case of Ne+U collision at 400 Me V! A. l ) (which are referred to as I hereafter) we investigated a possible microscopic mechanism for shock wave generation in high energy heavy ion collisions. The nuclear excitation induced by a nuclear collision was de­ scribed in terms of phonons. It was shown that as the collision proceeds phonons are coherently excited and show a characteristic feature of the shock wave. In this treatment the action of the projectile on the target was replaced by that of a potential moving with a constant velocity. We may construct this potential by superposing the nucleonic potential between projectile nucleons and the target ones with amplitudes of nucleonic states in both nuclei. To treat both systems equally from a microscopic viewpoint, one of the authors (M.I) proposed a formalism which is essentially an application of the Glauber approximation to the process. 2 ) The assembly of nucleons in the projectile nucleus was assumed to move in a group during the collision and the Glauber approximation was applied to the relative motion between the centers of masses of the projectile and the target nucleus. In this treatment the deceleration of the relative motion due to the nuclear excitation was not taken into account. In this paper we extend the Glauber approximation so as to take into account the slowing down of the relative motion. In § 2 the formulation of the modified Glauber approximation is presented.
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.
123223657
A Vibrational Bag Model for Baryons
Surface monopole vibration of baryons is investigated on the basis of the soliton bag model. We derive a relativistic Lagrangian for the surface motion whose mass parameter is proportional to square of the bag radius. With the use of the WKB approximation, the energy spectra of Pl1 and F" resonances are reproduced by our model fairly well. The static properties of the nucleon are alsO studied in our vibrational bag model and compared with those of the static bag model. Our model predicts that the nucleon consists of the central high·density part and the surrounding low-density part. It is also shown that our model is capable to predict the experimental data as well as the static bag model.
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.