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Scientific article
Open access
English

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

ContributorsATLAS Collaboration
Published inEuropean physical journal. C, Particles and fields, vol. 83, no. 9, 824
Publication date2023
First online date2023-09-15
Abstract

A search for Majorana neutrinos in same-sign WW scattering events is presented. The analysis uses $\sqrt{s}= 13$ 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 same-sign WW scattering and WZ 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 $\vert V_{\mu N} \vert ^{2}$ as a function of the heavy Majorana neutrino’s mass $m_N$, and on the effective $\mu \mu $ Majorana neutrino mass $|m_{\mu \mu }|$.

eng
Keywords
  • P p: colliding beams
  • P p: scattering
  • W W: scattering
  • W: leptonic decay
  • Neutrino: Majorana: mass
  • Operator: Weinberg
  • Jet: hadronic
  • Final state: ((n)jet dilepton)
  • Seesaw model: Type I
  • Same sign
  • Muon: particle identification
  • Background
  • Sensitivity
  • Benchmark
  • Neutrino: mixing
  • Muon: transverse momentum
  • Transverse momentum: momentum spectrum
  • CERN LHC Coll
  • Rapidity
  • ATLAS
  • Mass: upper limit
  • Experimental results
  • 13000 GeV-cms
Citation (ISO format)
ATLAS Collaboration. Search for Majorana neutrinos in same-sign <i>WW</i> scattering events from <i>pp</i> collisions at √𝑠 = 13 TeV. In: European physical journal. C, Particles and fields, 2023, vol. 83, n° 9, p. 824. doi: 10.1140/epjc/s10052-023-11915-y
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Article (Published version)
Identifiers
ISSN of the journal1434-6044
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