Forward--Backward Asymmetry in B -> X_s l^+ l^- at the NNLL Level

Abstract

We report the results of a new calculation of soft-gluon corrections in B -> X_s l^+ l^- decays. In particular, we present the first calculation of bremsstrahlung and corresponding virtual terms to the lepton forward-backward asymmetry, which allows us to systematically include all contributions to this observable beyond the lowest non-trivial order. The new terms are important, for instance the position of the zero of the asymmetry receives corrections of O(10%). Using a different method, we also provide an independent check of recently published results on bremsstrahlung and infrared virtual corrections to the dilepton-invariant mass distribution.

Comments: 20 pages, 5 figures. v2: typo in (4.26) corrected; discussion on mu-dependence modified