A model for the B → XS + γ decay in the chromomagnetic background

We calculate the shape of the photon spectrum for the B → XS+γ decay in the presence of a background chromomagnetic field for the case of an SU (2) gauge group. The effect of the external field resembles the Zeeman effect — the parton model peak is split into two slightly asymmetric peaks, located around the kinematic endpoint. We investigate the analytic properties of the spectrum and calculate the total decay rate. This decay may serve as a model for the investigation of gluon condensate effects and their influence on the shape of the spectrum.