Weak decays of doubly heavy baryons: multi-body decay channels

The newly-discovered Xi(++)(cc) decays into the Lambda K-+(c)-pi(+)pi(+), but the experimental data has indicated that this decay is not saturated by any two-body intermediate state. In this work, we analyze the multi-body weak decays of doubly heavy baryons Xi(cc), Omega(cc), Xi(bc), Omega(bc), Xi(bb) and Omega(bb), in particular the three-body nonleptonic decays and four-body semileptonic decays. We classify various decay modes according to the quark-level transitions and present an estimate of the typical branching fractions for a few golden decay channels. Decay amplitudes are then parametrized in terms of a few SU(3) irreducible amplitudes. With these amplitudes, we find a number of relations for decay widths, which can be examined in future.