Search for right-handed $W$ bosons and heavy neutrinos with the ATLAS experiment

A search for heavy right-handed Majorana or Dirac neutrinos ($N_R$) and heavy right-handed $W$ gauge bosons ($W_R$) participating in the Keung-Senjanovi$\'{c}$ process has been performed in events with a pair of energetic electrons or muons, with opposite-sign charges, and two energetic jets. Events were selected from $pp$ collision data with an integrated luminosity of 36.1 fb$^{−1}$ collected by the ATLAS detector at $\sqrt{s}$ = 13 TeV. No significant deviations from the Standard Model expectation were observed. The results were interpreted within the theoretical frameworks of two forms of Left-Right Symmetric Model and lower limits were set on masses in the heavy right-handed W and neutrino mass plane, as well as upper limits on the Keung-Senjanovi$\'{c}$ process cross section multiplied by the branching fraction to $eejj$ or $\mu\mu jj$ . The excluded region extends to $m_{W_R}$ = 4.7 TeV for both Majorana and Dirac $N_R$ neutrinos. The $m_{N_R} > m_{W_R}$ region is explored for the first time by a search for the Keung-Senjanovi$\'{c}$ process at the LHC.