B physics

The bottom quark, beauty quark, or b quark, is an elementary particle of the third generation. It is a heavy quark with a charge of -1/3 e.

All quarks are described in a similar way by electroweak interaction and quantum chromodynamics, but the bottom quark has exceptionally low rates of transition to lower-mass quarks. The bottom quark is also notable because it is a product in almost all top quark decays, and is a frequent decay product of the Higgs boson.

For more information, see Wikipedia.