Photon helicity in Λb→pKγΛb→pKγ decays

Radiative decays of polarized ΛbΛb baryons represent an attractive possibility to measure the helicity of the photon emitted in the b→sγb→sγ quark transition and thus to subject the Standard Model to a stringent test at existing and future hadron colliders. The most abundant mode, Λ(1116)γΛ(1116)γ, is experimentally very challenging because of the long decay length of the Λ(1116)Λ(1116). We show that the experimentally more accessible Λb→pKγΛb→pKγ decays proceeding via Λ   resonances may be used to extract the photon helicity for sufficient ΛbΛb polarization, if the resonance spin does not exceed 3/2. A direct comparison of the potential of such resonance decays to assess the photon polarization at a hadron collider with respect to the decay to Λ(1116)Λ(1116) is given.