Weak decays of doubly heavy baryons: the 1/2 → 3/2 case

As a continuation of our previous work, we investigate the weak decays of doubly heavy baryons into a spin-3/2 singly or doubly heavy baryon. The light-front approach is adopted to handle the dynamics in the transitions, in which the two spectator quarks are approximated as a diquark. Results for the form factors are then used to calculate decay widths of semileptonic and nonleptonic processes. The flavor SU(3) symmetry and symmetry breaking effects in semileptonic decays modes are explored, and we point out that in the charm sector, there are sizable symmetry breaking effects. For nonleptonic decay modes, we study only the factorizable channels induced by external W-emission. We find that branching fractions for most 1/2 to 3/2 transitions are approximately one order of magnitude smaller than the corresponding ones for the 1/2 to 1/2 transitions. Parametric uncertainties are also investigated in detail. We suggest our experimental colleagues to search for the 1/2 to 1/2 process Xi(++)(cc) -> Xi(c)'(+)pi(+) and its 1/ 2 to 3/ 2 counterpart Xi(++)(cc) -> Xi('*+)(c)pi(+). Their branching ratios turn out to be around 5.00% and 1.02%. The former branching ratio is expected to be close to that of the recently discovered Xi(++)(cc) -> Xi(+)(c)pi(+) process.