For each particle of matter there exists an
equivalent particle with opposite quantum characteristics, called an
anti-particle. Particle and anti-particle pairs can be created by
large accumulations of energy and, conversely, when a particle meets
an anti-particle they annihilate with intense blasts of energy. At
the time of the big-bang, the large accumulation of energy must have
created an equal amount of particles and anti-particles. But in
everyday life we do not encounter anti-particles. The question,
therefore, is "What has happened to the anti-particles?"
BABAR
is a High Energy Physics experiment located at
SLAC National Accelerator Laboratory,
near
Stanford University,
in California.
The goal of the experiment is to study the
violation of charge and parity (CP) symmetry in the decays of B
mesons. This violation manifests itself as different behaviour
between particles and anti-particles and is the first step to
explain the absence of anti-particles in everyday life.
To study CP violation the BABAR
experiment exploits the 9.1 GeV electron beam and the 3 GeV positron
beam of the
PEP-II accelerator. The two beams
collide in the center of the experiment, producing
Υ(4S) mesons which decay into equal
numbers of B and anti-B mesons.
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