The Belle detector analyzes reactions at the e+e--collider KEKB at the KEK laboratory in Tsukuba, Japan. Because the center of mass energy is equal to the mass of the Y(4S) resonance and the Y(4S) meson decays into a pair of B mesons, it is called a B factory. By using different energies for the electron and positron beams it is possible to measure the difference in the decay times of the two B mesons. With this setup, the Belle experiment could confirm CP violation in the B0 meson system which was predicted by the theory of Kobayashi and Maskawa who were awarded the Nobel prize for their theory. Furthermore, the large data sample of the Belle experiment allows to perform several high precision measurements on a broad fieled of flavor physics research. The aim of these measurements is to observe deviations from the predictions of the standard model of particle physics to obtain evidence for new particles or interactions.
Contribution of the ETP
The ETP is a member of the Belle collaboration since 2008 and performs analyses of CP violation, rare decays and charm physics. Furthermore, we develop high performance analysis algorithms. We could, for example, more than double the number of fully reconstructed B mesons in the Belle dataset.