Search for long-lived heavy neutral leptons decaying in the CMS muon detectors in proton-proton collisions at s√ = 13 TeV

(CMS Collaboration) Hayrapetyan, Aram ; ... ; Giljanović, Duje ; Godinović, Nikola ; Lelas, Damir ; Šćulac, Ana ; Kovač, Marko ; Šćulac, Toni ; Bargassa, Pedrame ; Brigljević, Vuko ; Chitroda, Bhakti Kanulal ; Ferenček, Dinko ; Mishra, Saswat ; Starodumov, Andrey ; Šuša, Tatjana ; ... ; Roguljić, Matej ; ... ; Zhokin, Alexander (2024) Search for long-lived heavy neutral leptons decaying in the CMS muon detectors in proton-proton collisions at s√ = 13 TeV. Physical Review D - Particles, Fields, Gravitation and Cosmology, 110 . ISSN 2470-0010

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Abstract

A search for heavy neutral leptons (HNLs) decaying in the CMS muon system is presented. A data sample is used corresponding to an integrated luminosity of 138 fb−1 of proton-proton collisions at s√ = 13 TeV, recorded at the CERN LHC in 2016-2018. Decay products of long-lived HNLs could interact with the shielding materials in the CMS muon system and create hadronic and electromagnetic showers detected in the muon chambers. This distinctive signature provides a unique handle to search for HNLs with masses below 4 GeV and proper decay lengths of the order of meters. The signature is sensitive to HNL couplings to all three generations of leptons. Candidate events are required to contain a prompt electron or muon originating from a vertex on the beam axis and a displaced shower in the muon chambers. No significant deviations from the standard model background expectation are observed. In the electron (muon) channel, the most stringent limits to date are set for HNLs in the mass range of 2.1-3.0 (1.9-3.3) GeV, reaching mixing matrix element squared values as low as 8.6 (4.6) × 10−6.

Item Type:	Article
Uncontrolled Keywords:	High energy physics ; Experimental particle physics ; LHC ; CMS ; p p scattering ; p p colliding beams ; decay ; muon detector ; electromagnetic showers ; lepton mass ; neutral particle ; electron ; signature ; shielding ; CERN Lab ; CERN LHC Coll ; background ; neutrino mixing ; ; experimental results ; 13000 GeV-cms
Subjects:	NATURAL SCIENCES > Physics NATURAL SCIENCES > Physics > Physics of Elementary Particles and Fields
Divisions:	Division of Experimental Physics
Depositing User:	Sanja Jurković
Date Deposited:	09 Oct 2024 10:28
URI:	http://fulir.irb.hr/id/eprint/9150
DOI:	10.1103/PhysRevD.110.012004

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