A search for heavy neutral gauge bosons (Z 0 ) decaying into a pair of tau leptons is performed in proton-proton collisions at √s = 13 TeV at the CERN LHC. The data were collected with the CMS detector and
correspond to an integrated luminosity of 138 fb ⁻¹ . The observations are found to be in agreement with the
expectation from standard model processes. Limits at 95% confidence level are set on the product of the Z^'
production cross section and its branching fraction to tau lepton pairs for a range of Z^' boson masses. For a
narrow resonance in the sequential standard model scenario, a Z^' boson with a mass below 3.5 TeV is
excluded. This is the most stringent limit to date from this type of search.