arXiv:1212.2849·v1·High Energy Physics — Lattice
Radiative improvement of spin and Darwin terms in the NRQCD action
T. C. Hammant🇬🇧 · A. G. Hart🇬🇧 · G. M. von Hippel🇩🇪 · R. R. Horgan🇬🇧 · C. J. Monahan🇺🇸
Abstract
We present updated results for the radiative improvement of the \sigma.B term and the spin-dependent four-fermion terms in the lattice NRQCD action, and first results for the radiative corrections to the NRQCD Darwin term and spin-independent four-fermion terms. The spin-dependent terms have significant impact on getting the correct hyperfine splitting for both bottomonium and heavy-light mesons, while the spin-independent terms suffer from a conspiracy between lattice artifacts and severe IR divergences that complicates their evaluation.
Comments: 7 pages, 3 pdf figures; proceedings of 30th International Symposium on Lattice Field Theory, June 24-29, 2012, Cairns, Australia