出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We describe how the background field method can be applied to Non-Relativistic QCD (NRQCD) on the lattice in order to determine the one-loop radiative corrections to the coefficients of the NRQCD action in a manifestly gauge-covariant manner. As a first application, we compute the shift of the hyperfine splitting of bottomonium stemming from the one-loop corrections to the coefficient of the s ·B term in the NRQCD action and the spin-dependent four-fermion couplings arising at the one-loop level. This is found to bring the lattice predictions in line with experiment as well as greatly reducing O(a2) dependences. We report a preliminary estimate for the hyperfine splitting, calculated on a fine lattice, of 70(6)MeV.
