BaBar is a physics experiment on elementary particles at the SMAC near the university of Stanford in California. It is also the name of the detector used.
The purpose of the experiment is to study CP symmetry violation in meson B disintegrations. This violation is shown through different behaviours of particles and antiparticles. It is one of the keys needed to explain the absence of antiparticles in daily life.
To study CP violation, the BaBar experiment uses a 9.1 GeV electron beam and the 3 GeV positron beam of the PEP-II accelerator. The two beams collide in the BaBar detector, producing mesons.