Weak decays of doubly heavy baryons:Bcc→BD*

The discovery of Ξ_cc⁺⁺has inspired new interest in studying doubly heavy baryons.In this study,the weak decays of a doubly charmed baryon B_ccto a light baryon B and a charm meson D^*(either a pseudoscalar or a vector one)are calculated.Following our previous work,we calculate the short distance contributions under the factorization hypothesis,whereas the long distance contributions are modeled as the final state interactions,which are calculated with the one particle exchange model.We find that the B_cc→BD^*decays'branching ratios are obviously larger,as they receive contributions of more polarization states.Among the decays that we investigate,the following have the largest branching fractions:BR(Ξ_cc⁺⁺→∑⁺D^*+)∈[0.46%,3.33%]estimated with τΞ_cc⁺⁺=256 fs;BR(Ξ_cc⁺→AD^*+)∈[0.38%,2.63%]and BR(Ξ_cc⁺→∑⁰D^*+)∈[0.45%,3.16%]with τΞ_cc⁺⁺=45 fs;and BR(Ω_cc⁺→Ξ⁰D⁺)∈[0.27%,1.03%),BR(Ω_cc⁺→∑⁰D^*+)∈[0.07%,0.44%],and BR(Ω_cc⁺→∑⁰D^*+)∈[0.06%,0.45%] with τ_(Ω_cc)⁺=75 fs.By comparing the decay widths of pure color commensurate channels with those of pure bow-tie ones we find that the bow-tie mechanism plays an important role in charm decays.