Hyperfine Mass Splittings of Baryons Containing a Heavy Quark in Large N QCD

Abstract

The hyperfine mass splittings of baryons containing a heavy quark are derived at leading order in large $N$ QCD. Hyperfine splittings either preserve or violate heavy quark spin symmetry. Previous work proves that the splittings which preserve heavy quark spin symmetry are proportional to ${\mathbf{J}}^2$ at order $1/N$, where $J$ is the angular momentum of the light degrees of freedom of the baryon. This work proves that the splittings which violate heavy quark spin symmetry are proportional to $\mathbf{J}\cdot {\mathbf{S}}_{\mathbf{Q}}$ at order $1/(N{m}_Q)$ in the $1/N$ and $1/m_Q$ expansions.

Comments: (8 pages, no figures, uses harvmac), UCSD/PTH 93-20