QCD sum rules study of \Xi_c and \Xi_b baryons

Abstract

We use QCD sum rules to study the masses of the baryons ${\Xi }_c$ and ${\Xi }_b$. We work with a current where the strange and the light quarks are in a relative spin zero, at leading order in ${\alpha }_s$. We consider the contributions of condensates up to dimension six. For ${\Xi }_b$ we get $m_{{\Xi }_b}=(5.75\pm 0.25)\mathrm{GeV}$, and for ${\Xi }_c$ we get $m_{{\Xi }_c}=(2.5\pm 0.2)\mathrm{GeV}$, both in excelent agreement with the experimental values. We also make predictions to the state ${\Omega }_b(ssb)$ obtaining m_{\Omega_{b}}= (5.82\pm 0.23) GeV.

Comments: revised version accepted for publication in Phys. Lett. B. Includes a prediction to the state Omega_b(ssb)