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. 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 are measured in future, some of these relations may provide hints for exploration of new decay modes.
Categories: hep-ph hep-ex