Abstract
Tests of lepton universality in and decays where is either an electron or a muon are presented. The differential branching fractions of and decays are measured in intervals of the dilepton invariant mass squared. The measurements are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of . The results are consistent with the standard model and previous tests of lepton universality in related decay modes. The first observation of and decays is reported.
- Received 19 October 2021
- Accepted 29 March 2022
DOI:https://doi.org/10.1103/PhysRevLett.128.191802
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