Polarized radiative $\Lambda_b$ decays at LHCb

We present a study of decays of the type Lambda_b->Lambda(X) gamma, where Lambda(X) is a Lambda baryon of mass X and spin 1/2 or 3/2. Detailed calculations of decay amplitudes and angular distributions are carried out employing the helicity formalism, and used to derive observables sensitive to new physics. In particular we make use of the initial polarization of the Lambda_b baryon to probe the polarization of the photon emitted in b -> s transitions. Such a measurement can be used to probe the chirality of the effective Hamiltonian, and possibly to unveil physics beyond the Standard Model. An estimate of the LHCb sensitivity to this measurement is also given