Search for a right-handed W boson and a heavy neutrino in proton-proton collisions at √s = 13 TeV

A search is presented for a right-handed W boson (W _R) and a heavy neutrino (N), in a final state consisting of two same-flavor leptons (ee or μμ) and two quarks. The search is performed with the CMS experiment at the CERN LHC using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138 fb ⁻¹. The search covers two regions of phase space, one where the decay products of the heavy neutrino are merged into a single large-area jet, and one where the decay products are well separated. The expected signal is characterized by an excess in the invariant mass distribution of the final-state objects. No significant excess over the standard model background expectations is observed. The observations are interpreted as upper limits on the product of W _R production cross sections and branching fractions assuming that couplings are identical to those of the standard model W boson. For N masses m _N equal to half the W _R mass mWR (m _N = 0.2 TeV), mWR is excluded at 95% confidence level up to 4.7 (4.8) and 5.0 (5.4) TeV for the electron and muon channels, respectively. This analysis provides the most stringent limits on the W _R mass to date. [Figure not available: see fulltext.]