Search for Heavy Neutral Leptons in Decays of W Bosons Using a Dilepton Displaced Vertex in s=13  TeV pp Collisions with the ATLAS Detector

• Published in: Physical review letters Vol. 131; no. 6
• Main Authors: Aad, G, Abbott, B, Abbott, D.C, Abed Abud, A, Abeling, K, Abhayasinghe, D.K, Abidi, S.H, Aboulhorma, A, Abramowicz, H, Abreu, H, Abulaiti, Y, Abusleme Hoffman, A.C, Acharya, B.S, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Addepalli, S.V, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, A.A, Afik, Y, Agaras, M.N, Agarwala, J, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, J.A, Ahmad, A, Ahmadov, F, Ahmed, W.S, Ai, X, Aielli, G, Aizenberg, I, Akbiyik, M, Åkesson, T.P.A, Akimov, A.V, Al Khoury, K, Alberghi, G.L, Albert, J, Albicocco, P, Alconada Verzini, M.J, Alderweireldt, S, Aleksa, M, Aleksandrov, I.N, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, B.M.M, Allport, P.P, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, M.G, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor dos Santos, S.P, Amoroso, S, Amos, K.R, Amrouche, C.S, Ananiev, V, Anastopoulos, C, Andari, N, Andeen, T, Anders, J.K, Andrean, S.Y, Andreazza, A, Angelidakis, S, Angerami, A, Anisenkov, A.V, Annovi, A, Antel, C, Anthony, M.T, Antipov, E, Antonelli, M, Antrim, D.J.A, Anulli, F, Aoki, M, Aparisi Pozo, J.A, Aparo, M.A, Aperio Bella, L, Appelt, C, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, A.T.H
• Format: Journal Article
• Language: English
• Published: American Physical Society 2023
• Subjects: High Energy Physics - Experiment; Physics; flavor: oscillation; experimental results; neutrino: flavor; lepton: heavy; CERN LHC Coll; mass: hierarchy; dilepton: final state; ATLAS; neutrino: mass; W: leptonic decay; neutrino: mixing; background; neutrino: left-handed; track data analysis: vertex; p p: scattering; p p: colliding beams; 13000 GeV-cms; W: rare decay; neutral particle: long-lived
• DOI: 10.1103/PhysRevLett.131.061803
• EISSN: 1079-7114
• ISSN: 0031-9007; 1079-7114

A search for a long-lived, heavy neutral lepton ( N ) in 139  fb-1 of s=13  TeV pp collision data collected by the ATLAS detector at the Large Hadron Collider is reported. The N is produced via W → N μ or W → N e and decays into two charged leptons and a neutrino, forming a displaced vertex. The N mass is used to discriminate between signal and background. No signal is observed, and limits are set on the squared mixing parameters of the N with the left-handed neutrino states for the N mass range 3  GeV<m N <15  GeV . For the first time, limits are given for both single-flavor and multiflavor mixing scenarios motivated by neutrino flavor oscillation results for both the normal and inverted neutrino-mass hierarchies.