203024439
Recent results and current status of the muon g-2 experiment at BNL
The measurement of the (g−2) value of leptons provides a unique test of theory since it is the only quantity (unlike charge and mass) calculable in the framework of the Standard Model of elementary particles. The muon (g−2) experiment E821 is currently in progress at Brookhaven National Laboratory. Four data taking runs for positive muons and one run for negative muons were successfully accomplished in 1997–2000 and 2001, respectively. Results of the 1997–2000 runs have been published, thus completing our experiment for μ+. Data analysis for the 2001 run for μ− is currently in progress. To provide measurement of \(a_\mu = \tfrac{1} {2}(g - 2)_{\mu ^ - }\) at the same level of accuracy as for \(a_{\mu ^ + } = \tfrac{1} {2}(g - 2)_{\mu ^ + }\), we need to have one more data taking run.
124815658
Measure of the spatial size for the monopole excitation in proton scattering
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.
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
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.
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.
54880563
Design and Status of the SuperKEKB Accelerator Control Network System
We have upgraded the accelerator control network system for SuperKEKB, the next generation B-factory experiment in Japan. The designed network system has the higher performance based on the wider bandwidth data transfer, and more reliable and redundant configuration. For the SuperKEKB beamline construction and accelerator components maintenance, we have installed the new wireless network system consists with the Leaky Coaxial (LCX) cable antennas and collinear antennas into the 3 km circumference accelerator tunnel. In this paper, we describe the design and current status of the SuperKEKB accelerator control network system.
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.
119408373
Fluctuation modes in color-superconductors
We investigate fluctuation effects of a gap parameter in color-superconductors. The fluctuation modes in the super phase are described by two scalar fields of diquarks. One of them is a Nambu-Goldstone boson and the other is a diquark boson whose mass is about twice of the gap energy (an extended quasi-supersymmetry). In the normal phase the fluctuation becomes a precursory (soft) mode whose amplitude increases near the critical temperature.
125753081
Magnetic Field Measurement System for the SuperKEKB Final Focus Superconducting Magnets
SuperKEKB final beam focusing system consists of different types of superconducting magnets: 8 quadrupole magnets, 4 solenoids and 43 corrector coils. In order to measure the field performances of the magnets and the coils, KEK prepared one set of harmonic coil system during the production stage in a factory, and two sets of harmonic coil systems for the cold tests at 4K for the vertical cryostat test stand in KEK. In this paper, we report these magnetic field measurement systems