The rare decay B→Xsℓ+ℓ− to NNLL precision for arbitrary dilepton invariant mass Original Research Article

We present a new phenomenological analysis of the inclusive rare decay B→Xsℓ+ℓ−. In particular, we present the first calculation of the NNLL contributions due to the leading two-loop matrix elements, evaluated for arbitrary dilepton invariant mass. This allows to obtain the first NNLL estimates of the dilepton mass spectrum and the lepton forward–backward asymmetry in the high M2ℓ+ℓ− region, and to provide an independent check of previously published results in the low M2ℓ+ℓ− region. The numerical impact of these NNLL corrections in the high-mass region (M2ℓ+ℓ−>14.4 GeV2) amounts to −13% in the integrated rate, and leads to a reduction of the scale uncertainty to ±3%. The impact of non-perturbative contributions in this region is also discussed in detail.