About the Cover
Vol. 80 No. 4 (2004)
KEKB accelerator, also known as KEK “B-factory” is currently the highest luminosity electron-positron collider in the world.
Electrons and positrons collide at the middle of the Belle detector (shown in the photo) at 8 GeV (eight billion electron volt) and 3.5 GeV, respectively.
Electron and positron beam lines are the strings of various types of magnets painted in blue, red and oranges near the engineers.
The Belle detector, which weighs about 2,000 tons and is 10 meters tall, is a state-of-art precise measurement apparatus.
Cylinder in the top middle is a "chimney", a liquid helium recirculation module for the cooling of the large superconducting solenoid for the measurement of the particle momenta.
Below the chimney is a part of the K-meson and muon detectors. Big blue panels on each side of the central detector are the "End plate" muon detectors which are to be shutdown after the maintenance work.
Pairs of B-meson and anti B-meson are produced with the collision, and by studying the subtle differences of the various decay modes of these mesons, the researchers hope to understand why there is a symmetry breakdown between the matter and the anti-matter in our Universe.
Written by Public Relations Office, KEK.