The Interim Review (External Review) on B Factory Project
When the universe was created,
the amount of matters and anti-matters were considered to be the same.
However, present universe is dominated by matters. The B-Factory project
at KEK is to find out the reason why this had happened through the electron-positron
collider experiment.
The construction of the electron-positron collider started in 1994. The accelerator, KEKB, and the Belle detector were completed in 1998. Since June 1999, the international collaboration has been carrying out the experiment for over three years.
The evidence for the existence
of the "CP Violation" was presented at the International Conference
on High Energy Physics held in Rome in July, 2001, and attracted attention
from many physicists in the world. The Belle detector had accumulated integrated
luminosity of 100/fb by October 2002 which no accelerator in the world
had reached before, and is trying to accumulate integrated luminosity of
300/fb. The Belle group is continuing the accumulation of data, and analysis
to discover the mechanism for the "CP Violation" and for the
search for physics phenomena beyond the Standard model.
Under this situation, we would like to have an Interim Review by the experts from non KEK staffs on March 13th and 14th ,2003 to carry out the B-Factory project more effectively and efficiently.
(Requirement for the Review Committee is attached.)
The report of the review on the B-Factory project will be published as
soon as the completion of the report.
*CP Violation
The operation C (charge) is to
change particles into their antiparticles, and the operation P (parity)
changes particles into their mirror images. Physics law is invariant almost
all cases and the combination of C and P, which is called CP invariance.
CP was discovered to be violated at rare decays of K mesons in 1964. In
order to explain the mechanism of this CP violation, Makoto Kobayashi (now
at KEK) and Toshihide Maskawa (now at Kyoto University) proposed that if
there were 6 kinds of quarks, the CP violation could be explained naturally
by mixing of these quarks. When they proposed this theory, only 3 kinds
of quarks had been discovered. Since then all of the remaining 3 kinds
of quarks have been discovered in the order of their masses. According
to Kobayashi-Maskawa theory, we may observe large CP-violation at rare
decays of a B meson that includes bottom quark, the second heaviest quark
among six. The detection of this CP-violation at B-mesons is the most important
subject to be studied at B-factory of KEK.
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| Research Cooperation Division of the International Research Cooperation
Department. |
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Email: kyodo1@mail.kek.jp |
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