Heavy quark decays: Gate to new physics?

Abstract

Transitions between quarks of different fermion generations are governed by small parameters of the Standard Model. Precision studies of decays of the heavy bottom quark, which are currently underway at LHCb, CMS, ATLAS, and Belle II, may reveal virtual effects from new particles which are too heavy to be produced in current particle colliders. The talk addresses goals and methods of this field of research and discusses the decays $b\to s \mu\bar \mu$ and $b\to c\tau\nu$, whose observed decay pattern does not agree with the Standard-Model prediction. A possible class of new particles capable of mediating these decays comprise so-called leptoquarks, which are predicted in theories of unified gauge interactions.