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

A search for heavy right-handed Majorana or Dirac neutrinos (𝑁𝑅) and heavy right-handed 𝑊 bosons (𝑊𝑅) participating in the Keung-Senjanović (KS) process has been performed in events with a pair of energetic electrons or muons and two energetic jets. Events were selected from 𝑝𝑝 collision data with an integrated luminosity of 139 fb−1 collected by √𝑠 = 13 TeV. No significant deviations from the Standard Model the ATLAS detector at expectation were observed. The results are interpreted within the theoretical framework of the Left-Right Symmetric Models (LRSM) and lower limits are set on masses of the 𝑊𝑅 and 𝑁𝑅. For Majorana electron neutrinos, the excluded region extends to a 𝑊𝑅 mass of 5.6 TeV and a 𝑁𝑅 mass of 3.4 TeV. For Majorana muon neutrinos, 𝑊𝑅 masses of up to 5.7 TeV are excluded, and 𝑁𝑅 masses of up to 3.6 TeV. For Dirac electron neutrinos, the excluded region extends to a 𝑊𝑅 mass of 6 TeV and to a 𝑁𝑅 mass of 3.5 TeV. For Dirac muon neutrinos, 𝑊𝑅 masses of up to 5.8 TeV are excluded, and 𝑁𝑅 masses of up to 3.7 TeV. These limits improve upon previous results in the bibliography and are currently the most stringent in the world.