Weak decays of doubly heavy baryons: SU(3) analysis

Motivated by the recent LHCb observation of doubly charmed baryon Ξ cc + + in the Λ c + K - π + π + final state, we analyze the weak decays of doubly heavy baryons Ξ cc , Ω cc , Ξ bc , Ω bc , Ξ bb and Ω bb under the flavor SU(3) symmetry. The decay amplitudes for various semileptonic and nonleptonic decays are parametrized in terms of a few SU(3) irreducible amplitudes. We find a number of relations or sum rules between decay widths and CP asymmetries, which can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC. Moreover, once a few decay branching fractions have been measured in the future, some of these relations may provide hints for exploration of new decay modes.