Search for Heavy Neutral Leptons in Decays of W Bosons Using a Dilepton Displaced Vertex in Formula Presented Collisions with the ATLAS Detector

• Autor(a) principal: Castro, Nuno Filipe
• Data de Publicação: 2023
• Outros Autores: Onofre, A., ATLAS Collaboration
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/1822/87795
• topic: Ciências Naturais::Ciências Físicas

A search for a long-lived, heavy neutral lepton ( N ) in 139 fb - 1 of s = 13 TeV p p 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.