Omega_bbb excited-state spectroscopy from lattice QCD

Abstract

Triply heavy baryons are very interesting systems analogous to heavy quarkonia, but are difficult to access experimentally. Lattice QCD can provide precise predictions for these systems, which can be compared to other theoretical approaches. In this work, the spectrum of excited states of the Omega_bbb baryon is calculated using lattice NRQCD for the b quarks, and using a domain-wall action for the u, d and s sea quarks. The calculations are done for multiple values of the sea-quark masses, and for two different lattice spacings. The energies of states with angular momentum up to J=7/2 are calculated, and the effects of rotational symmetry breaking by the lattice are analyzed. Precise results are obtained even for the small spin-dependent energy splittings, and the contributions of individual NRQCD interactions to these energy splittings are studied. The results are compared to potential-model calculations.Comment: 8 pages, 5 figure