$B_c$ Spectroscopy from Lattice QCD

Abstract

We present first results for $B_c$ spectroscopy using Lattice Non-Relativistic QCD (NRQCD). For the NRQCD action the leading order spin-dependent and next to leading order spin-independent interactions have been included with tadpole-improved coefficients. We use multi-exponential fits to multiple correlation functions to extract ground and excited $S$ states and give accurate values for the $S$ state hyperfine splitting and the P state ($B_c^{\ast \ast }$) fine structure, including the effects of ${}^1{P}_1{/}^3{P}_1$ mixing.

Comments: 12 pages uuencoded latex file + 1 postscript figure