Radiative improvement of spin and Darwin terms in the NRQCD action

Abstract

We present updated results for the radiative improvement of the σ.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.

arXiv comment7 pages, 3 pdf figures; proceedings of 30th International Symposium on Lattice Field Theory, June 24-29, 2012, Cairns, Australia

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