Hight Energy Accelerator Research Organization (KEK)
KEK is the major center for
high energy experimental
research in
Japan. It was formed in 1997 as a combination
of three laboratories:
National Laboratory for High Energy
Physics,
Institute for Nuclear Study, and
Meson Science
Laboratory of
University of Tokyo. It is located in the
city of
Tsukuba about an hour and a half from
Narita Airport in
Tokyo and about 70 km from the Tokyo
bus station, if I'm not misreading the directions.
The two major experiments of interest to me are
BELLE and K2K. BELLE is the detector in their
asymmetric e+e- collider (8 GeV electron vs.
3.5 GeV positron), which hopes to make observations
of the B meson (made from one bottom quark
and a light anti-quark (or vice versa)) decaying
through modes which violate CP symmetry
(CP = charge conjugation plus parity). These
observations will give clues about the nature of
flavor-changing interactions, and whether or not
they are described by the Standard Model or
require new physics. BELLE is "competing" with
a similar experiment called BaBar at SLAC.
K2K is a long baseline neutrino oscillation
experiment, where a neutrino beam is created at
KEK and directed towards the Super Kamiokande
detector 250 km away. Past experiments at Super Kamiokande
have detected solar neutrinos and atmospheric neutrinos
in order to detect the oscillation of neutrinos
from one flavor to another, say muon neutrino to
electron neutrino. These oscillations imply that
neutrinos have mass and mix with each other,
inducing flavor changing similar to the quarks.
Using KEK as a source of neutrinos will greatly
reduce uncertainties in these observations, since
one can measure the neutrino beam at the source as
well as at the detector. This contrasts solar and
atmospheric neutrinos where assumptions about and
models of the neutrino source
are required.
Of course, there is much, much more going on at KEK
besides these two experiments. You should explore
http://www.kek.jp to learn more.