Quenched and first unquenched lattice HQET determination of the Bs-meson width difference

Abstract

We present recent results for the prediction of the B 0 s - B 0 s lifetime difference from lattice Heavy Quark Effective Theory simulations. In order to get a next-to-leading order result we have calculated the matching between QCD and HQET and the two-loop anomalous dimensions in the HQET for all the Δ B=2 operators, in particular for the operators which enter the width difference. We present results from quenched and, for the first time, from unquenched simulations. We obtain for the B 0 s - B 0 s lifetime difference, ▪ and ▪ from the quenched and unquenched simulations respectively.