Heavy baryon spectroscopy from the lattice

The results of an exploratory lattice study of heavy baryon spectroscopy are presented. We have computed the full spectrum of the eight baryons containing a single heavy quark, on a ${24}^3$×48 lattice at $\beta =6.2\mathrm{}$, using an $O\left(a\right)\mathrm{}$--improved fermion action. We discuss the lattice baryon operators and give a method for isolating the contributions of the spin doublets ($\Sigma , {\Sigma }^{*}$), (${\Xi }^{\prime }, {\Xi }^{*}$), and ($\Omega , {\Omega }^{*}$) to the correlation function of the relevant operator. We compare our results with the available experimental data and find good agreement in both the charm and the $b$-quark sectors, despite the long extrapolation in the heavy quark mass needed in the latter case. We also predict the masses of several undiscovered baryons. We compute the $\Lambda$-pseudoscalar meson and $\Sigma -\Lambda$ mass splittings. Our results, which have errors in the range 10-30%, are in good agreement with the experimental numbers. For the ${\Sigma }^{*}-\Sigma$ mass splitting, we find results considerably smaller than the experimental values for both the charm and the $b$-flavored baryons, although in the latter case the experimental results are still preliminary. This is also the case for the lattice results for the hyperfine splitting for the heavy mesons.