A search for the charged-lepton-flavor-violating process Z→eμ is presented, using 139 fb−1 of √s = 13 TeV pp collision data collected by the ATLAS experiment at the LHC. An excess in the eμ invariant mass spectrum near the Z boson mass would be a striking signature of new physics. No excess is observed, and an upper limit B(Z→eμ)<2.62×10−7 is placed on the branching fraction at 95% confidence level, which is related to a ratio of the observed eμ yield to the average of the observed yields of ee and μμ events to significantly reduce systematic uncertainties.
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Accepted/In press - 7 Jul 2022|
Bibliographical noteNot yet published as of 08/08/2022
14 pages in total, 2 figures, 3 tables, submitted to Phys. Rev. D. All figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2018-35/