119500971
Possible existence of new medium interactions and 3.1- and 3.7-GeV particles
54175451
MUSIC, THE WORLD'S HIGHEST INTENSE DC MUON BEAM USING A PION CAPTURE SYSTEM
MuSIC is a project to provide the world’s highestintensity muon beam with continuous time structure at Research Center of Nuclear Physics (RCNP) of Osaka University, Japan. A pion capture system using a superconducting solenoid magnet and a part of superconducting muon transport solenoid channel have been build in 2009. The highest muon production efficiency was demonstrated by the beam tests. Results of the beam test conclude that the MuSIC can provide more than 10 8 muons/sec using a 400 W proton beam.
162176254
Development on Electromagnetic Calorimeter for COMET / PRISM
121688519
Symmetries and the mass ratio of the electron and muon
A model of symmetries and gauge interactions relating the electron and muon is considered. The model is based on the UL(1)⊗UR(1)⊗RL⊗RR group where UL(1)⊗UR(1) denotes the chiral e-μ rotation and RL⊗RR the chiral reflection of the electron field. The invariance under this group is spontaneously broken by the vacuum expectation values of scalar fields. A zeroth-order vacuum is found for which the zeroth-order electron mass vanishes, while one-loop corrections lead to a finite memμ ratio. The decay process μ → e + γ is strictly forbidden in this model.
122497415
R&D on Proton Extinction Monitor for COMET Project
The COMET experiment searches for a muon to electron conversion process that is one of the lepton flavor violation processes. We use an 8‐GeV pulsed proton beam. The proton extinction ratio is an important parameter. In order to measure this ratio pulse‐by‐pulse, we are developing a monitoring device. This device is called Proton Extinction Monitor and is a gas Cerenkov detector with gating photomultiplier tubes(PMT). The result of the investigation is that ethane is a promising gas for the Cerenkov radiator gas. A gating PMT is under development. We fabricated a divider circuit which switches at 10‐kHz and has a cutoff ratio of 10−6.
8106301
ZZ brane amplitudes from matrix models
We study instanton contribution to the partition function of the one matrix model in the k-th multicritical region, which corresponds to the (2,2k−1) minimal model coupled to Liouville theory. The instantons in the one matrix model are given by local extrema of the effective potential for a matrix eigenvalue and identified with the ZZ branes in Liouville theory. We show that the 2-instanton contribution in the partition function is universal as well as the 1-instanton contribution and that the connected part of the 2-instanton contribution reproduces the annulus amplitudes between the ZZ branes in Liouville theory. Our result serves as another nontrivial check on the correspondence between the instantons in the one matrix model and the ZZ branes in Liouville theory, and also suggests that the expansion of the partition function in terms of the instanton numbers are universal and gives systematically ZZ brane amplitudes in Liouville theory.
126008905
An Asymmetric collider with the TRISTAN Main Ring