arXiv:hep-ph/0208088v2 19 Sep 2002 CERN–TH/2002–161 July 2002 Forward–Backward Asymmetry in B → X s ℓ + ℓ − at the NNLL Level A. Ghinculov, a, 1 T. Hurth, b, 2 G. Isidori, b,c Y.-P. Yao d,1 a Department of Physics and Astronomy UCLA, Los Angeles CA 90095-1547, USA b Theoretical Physics Division, CERN, CH-1211 Geneva 23, Switzerland c INFN, Laboratori Nazionali di Frascati, I-00044 Frascati, Italy d Randall Laboratory of Physics University of Michigan, Ann Arbor MI 48109-1120, USA 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 corre- sponding 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. 1 Work supported by the U.S. Department of Energy (DOE). 2 Heisenberg Fellow.