[1] Univ Tsukuba, Inst Phys, Tsukuba, Ibaraki 305, Japan
[2] Univ Tsukuba, Ctr Computat Phys, Tsukuba, Ibaraki 305, Japan
[3] KEK, High Energy Accelerator Res Org, Ctr Res Comp, Tsukuba, Ibaraki 305, Japan
[4] KEK, High Energy Accelerator Res Org, Inst Particle & Nucl Studies, Tsukuba, Ibaraki 305, Japan