Affiliation: | (1) Institute for Laser Science (ILS), University of Electro-Communication, 1-5-1, Chofugaoka, Chofu, Tokyo, 182-0021, Japan E-mail:;(2) Center for Nuclear Study, University of Tokyo, 3-2-1, Midoricho, Tanashi, Tokyo 188-0002, Japan;(3) High Energy Accelerator Research Organization (KEK), Tanashi-branch, Institute of Particle and Nuclear Studies (IPNS), 3-2-1, Midoricho, Tanashi, Tokyo, 188-8501, Japan E-mail:;(4) Institute for Physics, University of Mainz, D-55099 Mainz, Germany |