Doubly heavy Baryons from QCD Spectral Sum Rules

We consider the ratios of doubly heavy baryon masses using Double Ratios of Sum Rules (DRSR), which are more accurate than the usual simple ratios used for getting hadron masses. Our results are comparable with the ones from potential models. In our approach, the αs corrections induced by the anomalous dimensions of the correlators are the main sources of the ΞQQ⁎−ΞQQ mass-splittings, which seem to indicate a 1/MQ behaviour and can only allow the electromagnetic decay ΞQQ⁎→ΞQQ+γ but not to ΞQQ+π. Our results also show that the SU(3) mass-splittings are (almost) independent of the spin of the baryons and behave approximately like 1/MQ, which could be understood from the QCD expressions of the corresponding two-point correlator. Our results can improved by including radiative corrections to the SU(3) breaking terms and can be tested, in the near future, at Tevatron and LHCb.