T. Mibe

New g 2 experiment at J-PARC

A new measurement of the anomalous magnetic moment of the positive muon aμ is proposed with a novel technique utilizing an ultra-cold muon beam accelerated to 300 MeV/c and a 66 cm-diameter muon storage ring without focusing-electric field. This measurement will be complimentary to the previous measurement that achieved 0.54 ppm accuracy with the magic energy of 3.1 GeV in a 14 m diameter storage ring. The proposed experiment aims to achieve the sensitivity down to 0.1 ppm.

Development of high intensity laser-electron photon beams up to 2.9 GeV at the SPring-8 LEPS beamline

Abstract A laser-Compton backscattering beam, which we call a ‘Laser-Electron Photon’ beam, was upgraded at the LEPS beamline of SPring-8. We accomplished the gains in backscattered photon beam intensities by factors of 1.5–1.8 with the injection of two adjacent laser beams or a higher power laser beam into the storage ring. The maximum energy of the photon beam was also extended from 2.4xa0GeV to 2.9xa0GeV with deep-ultraviolet lasers. The upgraded beams have been utilized for hadron photoproduction experiments at the LEPS beamline. Based on the developed methods, we plan the simultaneous injection of four high power laser beams at the LEPS2 beamline, which has been newly constructed at SPring-8. As a simulation result, we expect an order of magnitude higher intensities close to 10 7 xa0s −1 and 10 6 xa0s −1 for tagged photons up to 2.4xa0GeV and 2.9xa0GeV, respectively.

Enhancement of muonium emission rate from silica aerogel with a laser-ablated surface

e ) atoms from a laser-processed aerogel surface into vacuumwas studied for the rst time. Laser ablation was used to create hole-like regions withdiameter of about 270 x16m in a triangular pattern with hole separation in the range of300{500 x16m. The emission probability for the laser-processed aerogel sample is at leasteight times higher than for a uniform one.

Measurement of Muonium Hyperfine Splitting at J-PARC

J-PARC K. S. Tanaka1,3, M. Aoki4, H. Iinuma2, Y. Ikedo2, K. Ishida3, M. Iwasaki3, K. Ueno2, Y. Ueno1, T. Okubo2, T. Ogitsu2, R. Kadono2, O. Kamigaito3, N. Kawamura2, D. Kawall8, S. Kanda2,6, K. Kubo7, A. Koda2, K. M. Kojima2, N. Saito2, N. Sakamoto3, K. Sasaki2, K. Shimomura2, M. Sugano2, M. Tajima1, D. Tomono9, A. Toyoda2, H. A. Torii1, E. Torikai5, K. Nagamine2, K. Nishiyama2, P. Strasser2, Y. Higashi1, T. Higuchi1, Y. Fukao2, Y. Fujiwara6, Y. Matsuda1, T. Mibe2, Y. Miyake2, T. Mizutani1, M. Yoshida2, and A. Yamamoto2

J-PARC MUSE H-line optimization for the g-2 and MuHFS experiments

Significant deviation of the anomalous magnetic moment value (g-2) observed by the muon g-2 experiment should be confirmed by the other experiment. This value is experimentally determined by frequency difference observed by the g-2/EDM experiment and muon magnetic moment observed by the muonium hyperfine splitting experiment (MuHFS). Both two experiments are planned to be performed at H-line of the J-PARC/MUSE under construction. We optimized the beamline layout for each experiment with G4beamline. For both experiments, statistics is the most important, thus beamline transmission efficiency should be maximized. Especially for the g-2, the purpose of the present effort is to compromise between small beam size and small leakage field. For the MuHFS, it is crucial to minimize leakage field at around final focus position, and to get all stopped muons within good field region of MuHFS magnet. Conceptual design of the several final focusing systems will be presented. contribution (or invited paper) to NUFACT 11, XIIIth International Workshop on Neutrino Factories, Super beams and Beta beams, 1-6 August 2011, CERN and University of Geneva

Measurement of muonium emission from silica aerogel

Emission of muonium (

Study on Field Measurement and Ground Vibration for Superconducting Solenoid of New g-2 Experiment at J-PARC

mu^{+}e^{-}

Precise Measurement of Muonium HFS at J-PARC MUSE

) atoms from silica aerogel into vacuum was observed. Characteristics of muonium emission were established from silica aerogel samples with densities in the range from 29 mg cm

Precision Measurement of Muonium Hyperfine Splitting at J-PARC and Integrated Detector System for High-Intensity Pulsed Muon Beam Experiment

^{-3}

Development of High-Rate Positron Tracker for the Muonium Production Experiment at J-PARC

to 178 mg cm