Reconstruction of the decays $\Lambda_b \to \Lambda(1115) \gamma$ and $\Lambda_b \to \Lambda(1670) \gamma$ at LHCb

Polarized radiative Lambda_b decays represent an important sector to search for physics beyond the Standard Model. The LHC will present a fine opportunity for such a study, due to the large number of b hadrons that will be produced in pp collisions. We present the reconstruction of the decays Lambda_b -> Lambda(1115) gamma and Lambda_b -> Lambda(1670) gamma at LHCb. We find annual signal yields of about 750 events for the first and 2500 for the second channel. We assume that the dominant background comes from bb events and estimate the background to signal ratio B/S to be respectively less than 42 and 18 at 90% confidence level.