Physics Plan at JLC

The e+e− Linear Collider project, so called JLC, is the next principal project for research in high energy physics in Japan[1]. The JLC project consists of two experimental phases. The first phase (JLC-1) is an e+e− linear collider at 250 < √ s < 500GeV[2], and the second phase will extend the center-of-mass energy to > 1TeV[1, 3]. Although the JLC was originally proposed as a national project more than 10 years ago, the recent Subcommittee on Future Projects of High Energy Physics in Japan recommended that ”the Linear Collider should be hosted by Japan, and while the construction will be realized by international collaboration with Japan playing a key role, the experiment will be done on an international and open collaboration basis”[1]. In this spring, Asian Committee for Future Accelerators (ACFA) has initiated a physics and detector working group[4] under ACFA, considering the importance of the linear collider project and the potential of our community to realize it. The charge of the group is ”to elucidate physics scenario and experimental feasibilities and to write up a report to ACFA within two years”.