A search for long-lived heavy neutrinos (N) in the decays of B mesons produced in proton-proton collisions at root s = 13 TeV is presented. The data sample corresponds to an integrated luminosity of 41.6 fb(-1) collected in 2018 by the CMS experiment at the CERN LHC, using a dedicated data stream that enhances the number of recorded events containing B mesons. The search probes heavy neutrinos with masses in the range 1 < m(N) < 3 GeV and decay lengths in the range 10(-2) < c tau(N) < 10(4) mm, where tau(N) is the N proper mean lifetime. Signal events are defined by the signature B -> l(B)NX; N -> l(+/-)pi(-/+), where the leptons l(B) and l can be either a muon or an electron, provided that at least one of them is a muon. The hadronic recoil system, X, is treated inclusively and is not reconstructed. No significant excess of events over the standard model background is observed in any of the l(+/-)pi(-/+) invariant mass distributions. Limits at 95% confidence level on the sum of the squares of the mixing amplitudes between heavy and light neutrinos, vertical bar V-N vertical bar(2), and on c tau(N) are obtained in different mixing scenarios for both Majorana and Dirac-like N particles. The most stringent upper limit vertical bar V-N vertical bar(2) < 2.0 x 10(-5) is obtained at m(N) = 1.95 GeV for the Majorana case where N mixes exclusively with muon neutrinos. The limits on vertical bar V-N vertical bar(2) for masses 1 < m(N) < 1.7 GeV are the most stringent from a collider experiment to date.

Search for long-lived heavy neutrinos in the decays of B mesons produced in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

Bruschini, D.;
2024

Abstract

A search for long-lived heavy neutrinos (N) in the decays of B mesons produced in proton-proton collisions at root s = 13 TeV is presented. The data sample corresponds to an integrated luminosity of 41.6 fb(-1) collected in 2018 by the CMS experiment at the CERN LHC, using a dedicated data stream that enhances the number of recorded events containing B mesons. The search probes heavy neutrinos with masses in the range 1 < m(N) < 3 GeV and decay lengths in the range 10(-2) < c tau(N) < 10(4) mm, where tau(N) is the N proper mean lifetime. Signal events are defined by the signature B -> l(B)NX; N -> l(+/-)pi(-/+), where the leptons l(B) and l can be either a muon or an electron, provided that at least one of them is a muon. The hadronic recoil system, X, is treated inclusively and is not reconstructed. No significant excess of events over the standard model background is observed in any of the l(+/-)pi(-/+) invariant mass distributions. Limits at 95% confidence level on the sum of the squares of the mixing amplitudes between heavy and light neutrinos, vertical bar V-N vertical bar(2), and on c tau(N) are obtained in different mixing scenarios for both Majorana and Dirac-like N particles. The most stringent upper limit vertical bar V-N vertical bar(2) < 2.0 x 10(-5) is obtained at m(N) = 1.95 GeV for the Majorana case where N mixes exclusively with muon neutrinos. The limits on vertical bar V-N vertical bar(2) for masses 1 < m(N) < 1.7 GeV are the most stringent from a collider experiment to date.
Search for long-lived heavy neutrinos in the decays of B mesons produced in proton-proton collisions at √s=13 TeV
2024
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
Beyond Standard Model; Hadron-Hadron Scattering; Lifetime; Baryon Asymmetry; Dark-Matter
   Advanced Multi-Variate Analysis for New Physics Searches at the LHC
   AMVA4NewPhysics
   European Commission
   Horizon 2020 Framework Programme
   675440

   Search for Higgs bosons decaying to charm quarks
   HIGCC
   European Commission
   Horizon 2020 Framework Programme
   724704

   Direct and indirect searches for new physics in events with top quarks using LHC proton-proton collisions at the CMS detector
   LHCTOPVLQ
   European Commission
   Horizon 2020 Framework Programme
   752730

   Majorana neutrino discovery strategy with CMS
   MajorNet
   European Commission
   Horizon 2020 Framework Programme
   758316

   International Training Network for Statistics in High Energy Physics and Society
   INSIGHTS
   European Commission
   Horizon 2020 Framework Programme
   765710

   The strong interaction at the frontier of knowledge: fundamental research and applications
   STRONG-2020
   European Commission
   Horizon 2020 Framework Programme
   824093

   International, Interdisciplinary & Intersectoral Postdoctoral Fellowships at the Paul Scherrer Institut
   PSI-FELLOW-III-3i
   European Commission
   Horizon 2020 Framework Programme
   884104

   Quantum Universe
   Deutsche Forschungsgemeinschaft
   Exzellenzcluster (ExStra)
   390833306
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/154876
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