Test of lepton universality in $b \rightarrow s \ell^+ \ell^-$ decays

TL;DR

This paper reports the first simultaneous test of muon-electron universality in specific B meson decays using LHCb data, finding results consistent with the Standard Model across different invariant mass ranges.

Contribution

It presents the first combined analysis of muon-electron universality in B decays across multiple channels and q^2 ranges, improving upon previous measurements.

Findings

Results are compatible with Standard Model predictions.

First measurements in certain q^2 intervals.

Supersedes previous LHCb measurements.

Abstract

The first simultaneous test of muon-electron universality using $B^{+}\rightarrow K^{+}\ell^{+}\ell^{-}$ and $B^{0}\rightarrow K^{*0}\ell^{+}\ell^{-}$ decays is performed, in two ranges of the dilepton invariant-mass squared, $q^{2}$. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 $\mathrm{fb}^{-1}$. Each of the four lepton universality measurements reported is either the first in the given $q^{2}$ interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.