Thank you all SOKENDAI professors for SOKENDAI award. I am deeply honored to receive this award. I greatly appreciate the support of SOKENDAI and KEK during studying in PhD. I would like to express my special appreciation and thanks to my supervisors, without their guidance and constant feedback, this study would not have been achievable. I also would like to express my sincere gratitude to my family and all those who supported me. This award is one of motivation to continue the research and devote myself to become a good scientist.