1. Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0821, Japan
2. Materials and Life Science Division, Japan Proton Accelerator Research Complex (J-PARC), Tokai, Ibaraki 319-1195, Japan
3. Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
4. TRIUMF, Vancouver, BC V6T 2A3, Canada
5. Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0821, Japan
6. Particle and Nuclear Physics Division, Japan Proton Accelerator Research Complex (J-PARC), Tokai, Ibaraki 319-1195, Japan
7. Graduate School of Science, Osaka City University, Sumiyoshi, Osaka 558-8585, Japan
8. Present address: Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
9. Present address: Accelerator Division, Japan Proton Accelerator Research Complex (J-PARC), Tokai, Ibaraki 319-1195, Japan
10. Japan Proton Accelerator Research Complex (J-PARC), Tokai, Ibaraki 319-1195, Japan