1. Graduate University for Advanced Studies (SOKENDAI), High Energy Accelerator Research Organization (KEK), Tsukuba, Japan
2. KEK, Tsukuba, Ibaraki, Japan
3. National Institute for Materials Science (NIMS), Tsukuba, Japan
4. Institute for Material Research, Tohoku University, Sendai, Japan
5. Kobe Steel Ltd., Kobe, Japan
6. European Organization for Nuclear Research (CERN), Geneva, Switzerland