Uncovering tau leptons-enriched semi-visible jets at the LHC

Abstract

This Letter proposes a new signature for confining dark sectors at the Large Hadron Collider. Under the assumption of a QCD-like hidden sector, hadronic jets containing stable dark bound states could manifest in proton-proton collisions. We present a simplified model with a $Z^{\prime }$ boson yielding the production of jets made up of dark bound states and subsequently leading to the decays of those that are unstable to $\tau$ leptons and Standard Model quarks. The resulting signature is characterised by non-isolated $\tau$ lepton pairs inside semi-visible jets. We estimate the constraints on our model from existing CMS and ATLAS analyses. We propose a set of variables that leverage the leptonic content of the jet and exploit them in a supervised jet tagger to enhance the signal-to-background separation. Furthermore, we discuss the performance and limitations of current triggers for accessing sub-TeV $Z^{\prime }$ masses, as well as possible strategies that can be adopted by experiments to access such low mass regions. We estimate that with the currently available triggers, a high mass search can claim a $5\sigma$ discovery (exclusion) of the $Z^{\prime }$ boson with a mass up to 4.5TeV (5.5TeV) with the full Run2 data of the LHC when the fraction of unstable dark hadrons decaying to $\tau$ lepton pairs is around $50\%$, and with a coupling of the $Z^{\prime }$ to right-handed up-type quarks of 0.25. Furthermore, we show that, with new trigger strategies for Run3, it may be possible to access $Z^{\prime }$ masses down to 700 GeV, for which the event topology is still composed of two resolved semi-visible jets.

arXiv comment11 pages, 8 figures, 2 tables, (published on EPJ C as Letter)

References in corpus (45)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• The anti-k_t jet clustering algorithm
• Particle Dark Matter: Evidence, Candidates and Constraints
• FastJet user manual
• Supersymmetric Dark Matter
• Asymptotic formulae for likelihood-based tests of new physics
• DELPHES 3, A modular framework for fast simulation of a generic collider experiment
• LHAPDF6: parton density access in the LHC precision era
• Confidence Level Computation for Combining Searches with Small Statistics
• Particle-flow reconstruction and global event description with the CMS detector
• Echoes of a Hidden Valley at Hadron Colliders
• TMVA - Toolkit for Multivariate Data Analysis
• Parton distributions with QED corrections
• Neutrino Trident Production: A Powerful Probe of New Physics with Neutrino Beams
• Electron and photon performance measurements with the ATLAS detector using the 2015-2017 LHC proton-proton collision data
• Jet reconstruction and performance using particle flow with the ATLAS Detector
• Dressing L_mu - L_tau in Color
• Search for high-mass dilepton resonances using 139 fb${}^{-1}$ of $pp$ collision data collected at $\sqrt{s}=$13 TeV with the ATLAS detector
• Search for new phenomena in the dijet mass distribution using $p-p$ collision data at $\sqrt{s}=8$ TeV with the ATLAS detector
• Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC
• Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at sqrt(s) = 8 TeV
• Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb${}^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Search for new resonances in mass distributions of jet pairs using 139 fb${}^{-1}$ of $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Semi-visible Jets: Dark Matter Undercover at the LHC
• Search for narrow and broad dijet resonances in proton-proton collisions at $\sqrt{s}=$ 13 TeV and constraints on dark matter mediators and other new particles
• Search for high mass dijet resonances with a new background prediction method in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Search for high-mass resonances in dilepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Visible Effects of Invisible Hidden Valley Radiation
• SoftKiller, a particle-level pileup removal method
• Search for low-mass dijet resonances using trigger-level jets with the ATLAS detector in $pp$ collisions at $\sqrt{s}=13$ TeV
• LHC Searches for Dark Sector Showers
• Communication with SIMP dark mesons via Z'-portal
• Discerning Secluded Sector gauge structures
• An Effective Z'
• The Cosmology of Composite Inelastic Dark Matter
• Strongly interacting dark sectors in the early Universe and at the LHC through a simplified portal
• Twin SIMPs
• Dark matter in Hidden Valley models with stable and unstable light dark mesons
• A comprehensive guide to the physics and usage of PYTHIA 8.3
• Collider phenomenology of Hidden Valley mediators of spin 0 or 1/2 with semivisible jets
• Search for resonant production of strongly coupled dark matter in proton-proton collisions at 13 TeV
• Relic Abundance in a Secluded Dark Matter Scenario with a Massive Mediator
• Classification of dark pion multiplets as dark matter candidates and collider phenomenology
• Search for non-resonant production of semi-visible jets using Run 2 data in ATLAS
• Leptons lurking in semi-visible jets at the LHC

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