Search for a new Z' gauge boson in $4\mu$ events with the ATLAS experiment

Abstract

This paper presents a search for a new Z' vector gauge boson with the ATLAS experiment at the Large Hadron Collider using pp collision data collected at $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of 139 fb${}^{-1}$. The new gauge boson Z' is predicted by $L_{\mu }-L_{\tau }$ models to address observed phenomena that can not be explained by the Standard Model. The search examines the four-muon (4$\mu$) final state, using a deep learning neural network classifier to separate the Z' signal from the Standard Model background events. The di-muon invariant masses in the $4\mu$ events are used to extract the Z' resonance signature. No significant excess of events is observed over the predicted background. Upper limits at a 95% confidence level on the Z' production cross-section times the decay branching fraction of $pp\to Z^{\prime }\mu \mu \to 4\mu$ are set from 0.31 to 4.3 fb for the Z' mass ranging from 5 to 81 GeV. The corresponding common coupling strengths, $g_{Z^{\prime }}$, of the Z' boson to the second and third generation leptons above 0.003 - 0.2 have been excluded.

arXiv comment45 pages in total, author list starting at page 26, 7 figures, 3 tables, published by JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HDBS-2018-57/

References in corpus (37)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• An Introduction to PYTHIA 8.2
• A Brief Introduction to PYTHIA 8.1
• FastJet user manual
• Asymptotic formulae for likelihood-based tests of new physics
• A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX
• A New Method for Combining NLO QCD with Shower Monte Carlo Algorithms
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• FeynRules 2.0 - A complete toolbox for tree-level phenomenology
• Parton distributions for the LHC Run II
• Parton distributions with LHC data
• PDF4LHC recommendations for LHC Run II
• UFO - The Universal FeynRules Output
• Scattering Amplitudes with Open Loops
• The Physics of Heavy Z' Gauge Bosons
• A parton shower algorithm based on Catani-Seymour dipole factorisation
• A Positive-Weight Next-to-Leading-Order Monte Carlo for Heavy Flavour Hadroproduction
• QCD Matrix Elements + Parton Showers
• Comix, a new matrix element generator
• Event Generation with Sherpa 2.2
• PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays
• QCD matrix elements + parton showers: The NLO case
• High-precision QCD at hadron colliders: electroweak gauge boson rapidity distributions at NNLO
• Single-top Wt-channel production matched with parton showers using the POWHEG method
• QCD matrix elements and truncated showers
• Collier: a fortran-based Complex One-Loop LIbrary in Extended Regularizations
• Single-top hadroproduction in association with a W boson
• A critical appraisal of NLO+PS matching methods
• OpenLoops 2
• Trial factors for the look elsewhere effect in high energy physics
• Parameterized Machine Learning for High-Energy Physics
• Explaining Dark Matter and $B$ Decay Anomalies with an $L_{\mu }-L_{\tau }$ Model
• Gauged $L_{\mu }-L_{\tau }$ with Large Muon Anomalous Magnetic Moment and the Bimaximal Mixing of Neutrinos
• ZZ production at the LHC: fiducial cross sections and distributions in NNLO QCD
• Collider limits on leptophilic interactions
• Dark matter clues in the muon anomalous magnetic moment
• The Muon $g-2$ experiment at Fermilab

Cited by in corpus (6)

• Exploration at the high-energy frontier: ATLAS Run~2 searches investigating the exotic jungle beyond the Standard Model
• Probing chiral and flavored $Z^{\prime }$ from cosmic bursts through neutrino interactions
• Leptophilic $Z^{\prime }$ bosons at the FCC-ee: discovery opportunities
• Search for a new $Z^{\prime }$ gauge boson via the $pp\to W^{\pm (\ast )}\to Z^{\prime }{\mu }^{\pm }\nu \to {\mu }^{\pm }{\mu }^{\mp }{\mu }^{\pm }\nu$ process in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Probing a low-mass $Z^{\prime }$ gauge boson at IceCube and prospects for IceCube-Gen2
• Spin identification of the mono-Z${}^{\prime }$ resonance in muon-pair production at the ILC with simulated electron-positron collisions at $\sqrt{s}$ = 500 GeV