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Search for Majorana neutrinos in same-sign WW scattering events from pp collisions at √s = 13 TeV ATLAS Collaboration

Abstract

A search for Majorana neutrinos in same-sign W W scattering events is presented. The analysis uses √s = 13 TeV proton–proton collision data with an integrated luminosity of 140 fb−1 recorded during 2015–2018 by the ATLAS detector at the Large Hadron Collider. The analysis targets final states including exactly two same-sign muons and at least two hadronic jets well separated in rapidity. The modelling of the main backgrounds, from Standard Model samesign W W scattering and W Z production, is constrained with data in dedicated signal-depleted control regions. The distribution of the transverse momentum of the second-hardest muon is used to search for signals originating from a heavy Majorana neutrino with a mass between 50 GeV and 20 TeV. No significant excess is observed over the background expectation. The results are interpreted in a benchmark scenario of the Phenomenological Type-I Seesaw model. In addition, the sensitivity to the Weinberg operator is investigated. Upper limits at the 95% confidence level are placed on the squared muon-neutrino–heavy-neutrino mass-mixing matrix element |VμN | 2 as a function of the heavy Majorana neutrino’s mass mN , and on the effective μμ Majorana neutrino mass |mμμ|.

Item Metadata

Title
Search for Majorana neutrinos in same-sign WW scattering events from pp collisions at √s = 13 TeV
Creator
ATLAS Collaboration
Publisher
Springer Berlin Heidelberg
Date Issued
2023-09-15
Description
A search for Majorana neutrinos in same-sign W W scattering events is presented. The analysis uses √s = 13 TeV proton–proton collision data with an integrated luminosity of 140 fb−1 recorded during 2015–2018 by the ATLAS detector at the Large Hadron Collider. The analysis targets final states including exactly two same-sign muons and at least two hadronic jets well separated in rapidity. The modelling of the main backgrounds, from Standard Model samesign W W scattering and W Z production, is constrained with data in dedicated signal-depleted control regions. The distribution of the transverse momentum of the second-hardest muon is used to search for signals originating from a heavy Majorana neutrino with a mass between 50 GeV and 20 TeV. No significant excess is observed over the background expectation. The results are interpreted in a benchmark scenario of the Phenomenological Type-I Seesaw model. In addition, the sensitivity to the Weinberg operator is investigated. Upper limits at the 95% confidence level are placed on the squared muon-neutrino–heavy-neutrino mass-mixing matrix element |VμN | 2 as a function of the heavy Majorana neutrino’s mass mN , and on the effective μμ Majorana neutrino mass |mμμ|.
Genre
Article
Type
Text
Language
eng
Date Available
2023-11-08
Provider
Vancouver : University of British Columbia Library
Rights
Attribution 4.0 International (CC BY 4.0)
DOI
10.14288/1.0437561
URI
http://hdl.handle.net/2429/86471
Affiliation
Science, Faculty of; TRIUMF; Non UBC; Physics and Astronomy, Department of
Citation
The European Physical Journal C. 2023 Sep 15;83(9):824
Publisher DOI
10.1140/epjc/s10052-023-11915-y
Peer Review Status
Reviewed
Scholarly Level
Faculty
Copyright Holder
CERN for the benefit of the ATLAS Collaboration
Rights URI
http://creativecommons.org/licenses/by/4.0/
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Attribution 4.0 International (CC BY 4.0)