S- and P-wave heavy-light mesons in lattice nonrelativistic QCD - art. no.114507

The mass spectrum of S- and P-wave mesons containing a single heavy quark i s computed in the quenched approximation, using NRQCD up to third order in the inverse heavy quark mass expansion. Previous results found third order contributions which are as large in magnitude as the total second order con tribution for the charmed S-wave spin splitting. The present work considers variations such as anisotropic lattices, Landau link tadpole improvement, and a highly improved light quark action, and finds that the second order c orrection to the charmed S-wave spin splitting is about 20% of the leading order contribution, while the third order correction is about 20% (10%) for D*-D (D-s*-D-s). Nonleading corrections are very small for the bottom maso n spectrum, and are statistically insignificant for the P-wave charmed mass es. The relative orderings among P-wave charmed and bottom masons, and the sizes of the mass splittings, are discussed in light of experimental data a nd existing calculations.