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We apply the background field (BF) method 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 by matching the NRQCD prediction for particular on-shell processes with those of relativistic continuum QCD. We explain how the BF method is implemented in automated perturbation theory and discuss the technique for matching the relativistic and non-relativistic theories. We compute the one-loop radiative corrections to the sigma.B and Darwin terms for the NRQCD action currently used in simulations, as well as the one-loop coefficients of the spin-dependent O(alpha^2) four-fermion contact terms. The effect of the corrections on the hyperfine splitting of bottomonium is estimated using earlier simulation results; the corrected lattice prediction is found to be in agreement with experiment. Agreement of the hyperfine splitting of bottomonium and the B-meson system is confirmed by recent simulation studies (Dowdall et al.) which include our NRQCD radiative corrections for the first time.
We perform a nonperturbative determination of the $O(a)$-improvement coefficient $c_{rm SW}$ and the critical hopping parameter $kappa_c$ for $N_f$=3, 2, 0 flavor QCD with the RG-improved gauge action using the Schrodinger functional method. In order
I discuss NRQCD and, in particular, the NRQCD factorization formalism for quarkonium production and decay. I also summarize the current status of the comparison between the predictions of NRQCD factorization and experimental measurements.
The magnetic polarisability is a fundamental property of hadrons, which provides insight into their structure in the low-energy regime. The pion magnetic polarisability is calculated using lattice QCD in the presence of background magnetic fields. Th
Lattice calculations using the framework of effective field theory have been applied to a wide range few-body and many-body systems. One of the challenges of these calculations is to remove systematic errors arising from the nonzero lattice spacing.
The calculation of the light-hadron spectrum in the quenched approximation to QCD using an anisotropic clover fermion action is presented. The tuning of the parameters of the action is discussed, using the pion and rho dispersion relation. The adopti