The Working Group

In the 2nd plenary meeting, ACFA announced its endorsement of the e+e- linear collider as one of the major future facilities in the Asia-Pacific region. In fact, recent world-wide research at existing facilities has enabled us to form a more and more concrete picture of "TeV-scale physics" and, consequently, has made more and more crucial the e+e- linear collider's role in its exploration. According to the recent picture, the linear collider is expected to produce very important, decisive physics outputs even in the initial stage (in the energy region below 500GeV) of its energy upgrading program ; for instance, a top quark study at threshold, which is very important in its own right, can be a key to new physics and, more importantly, the Higgs particle will almost certainly manifest itself there or the SUSY/GUTS scenario will be disapproved.

In addition to its role as an energy frontier machine for High Energy Physics, the linear collider has a facet which can be shared with a new means for materials science. The ultra-low emittance beam essential to the linear collider is also an indispensable element of the next-generation, coherent x-ray source. In order to efficiently and effectively promote accelerator science in the region, one should start seriously thinking about the possibility of integrating both into a single project.

Turning our attention to activities in Asian region, we see significant progress in high energy and synchrotron radiation experiments at various domestic facilities. Not only that, many researchers from ACFA member nations are actively participating in large-scale experiments such as at LEP-II, Tevatron collider, HERA and PEP-II/KEKB. The Asian physics community on which ACFA is based has grown significantly and has set a firm enough foundation to prepare for further advancement.

In response to the ACFA statement issued in the last year, considering the importance of the linear collider project and the potential of our community to realize it, we set up a study group under ACFA. The charge of the group is to elucidate physics scenario and experimental feasibilities and to write up a report to ACFA within two years. Taking account of the scale of and the world-wide interests in such project, actual studies shall hopefully be carried out in a more global scope in spite of the regional nature of ACFA's initiative. KEK should play a secretarial role in the study.

Zhipeng Zheng
Asian Committee for Future Accelerators

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