Search for a right-handed W boson and a heavy neutrino in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

Abstract

Copyright © 2022 CERN, for the benefit of the CMS Collaboration. <jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A search is presented for a right-handed W boson (W<jats:sub>R</jats:sub>) 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<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. 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<jats:sub>R</jats:sub> production cross sections and branching fractions assuming that couplings are identical to those of the standard model W boson. For N masses <jats:italic>m</jats:italic><jats:sub>N</jats:sub> equal to half the W<jats:sub>R</jats:sub> mass <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {m}_{{\mathrm{W}}_{\mathrm{R}}} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>m</mml:mi> <mml:msub> <mml:mi>W</mml:mi> <mml:mi>R</mml:mi> </mml:msub> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula> (<jats:italic>m</jats:italic><jats:sub>N</jats:sub> = 0<jats:italic>.</jats:italic>2 TeV), <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {m}_{{\mathrm{W}}_{\mathrm{R}}} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>m</mml:mi> <mml:msub> <mml:mi>W</mml:mi> <mml:mi>R</mml:mi> </mml:msub> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula> 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<jats:sub>R</jats:sub> mass to date.</jats:p>