Precise predictions for B -> Xs l+ l- in the large q^2 region

TL;DR

This paper improves predictions for the B -> Xs l+ l- decay rate in the large q^2 region by reducing uncertainties through normalization techniques and including higher-order corrections, aiding experimental tests of the Standard Model.

Contribution

It provides a detailed calculation of the ratio of decay rates with nonperturbative and perturbative corrections, enhancing the precision of theoretical predictions in the large q^2 region.

Findings

Reduced theoretical uncertainties in B -> Xs l+ l- decay predictions.

Calculated ratio includes nonperturbative and NNLO perturbative corrections.

Results facilitate experimental tests at LHCb and studies of related decays.

Abstract

The inclusive B -> Xs l+ l- decay rate in the large q^2 region (q^2 > m_{\psi'}^2) receives significant nonperturbative corrections. The resulting uncertainties can be drastically reduced by normalizing the rate to the B -> Xu l nu rate with the same q^2 cut, which allows for much improved tests of short distance physics. We calculate this ratio, including the order 1/m_b^3 nonperturbative corrections and the analytically known NNLO perturbative corrections. Since in the large q^2 region an inclusive measurement may be feasible via a sum over exclusive states, our results could be useful for measurements at LHCb and possibly for studies of B -> Xd l+ l-.