Exclusive c → uγ transitions of Bc meson

Abstract

We study the rare decays of the Bc meson induced by the flavour changing neutral current c → uγ transition. In the Standard Model they are strongly suppressed by the Glashow-Iliopoulos-Maiani mechanism, therefore they are sensitive to new physics. The difficulty is to get rid of long-distance contributions. We study such effects in radiative Bc transitions both to B* and to the axial-vector B′1 meson.