B meson in the context of Bottom quark

Electron–positron annihilation occurs when an electron (e
) and a positron (e
, the electron's antiparticle) collide. At low energies, the result of the collision is the annihilation of the electron and positron, and the creation of energetic photons:

At high energies, other particles, such as B mesons or the W and Z bosons, can be created. All processes must satisfy a number of conservation laws, including:

The Belle experiment was a particle physics experiment conducted by the Belle Collaboration, an international collaboration of more than 400 physicists and engineers, at the High Energy Accelerator Research Organisation (KEK) in Tsukuba, Ibaraki Prefecture, Japan. The experiment ran from 1999 to 2010.

The Belle detector was located at the collision point of the asymmetric-energy electron–positron collider, KEKB. Belle at KEKB together with the BaBar experiment at the PEP-II accelerator at SLAC were known as the B-factories as they collided electrons with positrons at the center-of-momentum energy equal to the mass of the ϒ(4S) resonance which decays to pairs of B mesons.