Search for the Z Boson Decay to ττμμ in Proton-Proton Collisions at √s p = 13 TeV

The first search for the Formula Presented boson decay to Formula Presented at the CERN LHC is presented, based on data collected by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of Formula Presented. The data are compatible with the predicted background. For the first time, an upper limit at the 95% confidence level of 6.9 times the standard model expectation is placed on the ratio of the Formula Presented to Formula Presented branching fractions. Limits are also placed on the six flavor-conserving four-lepton effective-field-theory operators involving two muons and two tau leptons, for the first time testing all such operators.