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

Motivated by the recent LHCb observation of doubly charmed baryon $$\Xi _{cc}^{++}$$ in the $$\Lambda _c^+ K^-\pi ^+\pi ^+$$ final state, we analyze the weak decays of doubly heavy baryons $$\Xi _{cc}$$ , $$\Omega _{cc}$$ , $$\Xi _{bc}$$ , $$\Omega _{bc}$$ , $$\Xi _{bb}$$ and $$\Omega _{bb}$$ 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.