Doubly heavy Baryons from QCD Spectral Sum Rules

TL;DR

This paper uses Double Ratios of Sum Rules to accurately estimate doubly heavy baryon masses, revealing their dependence on heavy quark mass and SU(3) symmetry, with results aligning with potential models and testable at collider experiments.

Contribution

It introduces the use of Double Ratios of Sum Rules for more precise baryon mass predictions and analyzes their mass splittings and decay modes in the context of QCD.

Findings

Mass splittings behave like 1/M_Q.

Electromagnetic decay is favored over pion emission.

SU(3) mass-splittings are nearly independent of spin.

Abstract

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. The Xi^*_{QQ}-Xi_{QQ} splittings seem to behave like 1/M_Q and can only allow the electromagnetic decay Xi^*_{QQ} to Xi_{QQ}+gamma but not to Xi_{QQ}+ pi. Our results also show that the SU(3) mass-splittings are (almost) independent of the spin of the baryons and behave approximately like 1/M_Q, 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.