Inclusive nonresonant multilepton probes of new phenomena at $\sqrt{s}=$ 13 TeV

Abstract

An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying $\tau$ leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb${}^{-1}$ of proton-proton collisions at $\sqrt{s}=$ 13 TeV, collected by the CMS experiment at the LHC in 2016-2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845-1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vector-like $\tau$ lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125-150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12-1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vector-like doublet model, these constraints are the most stringent to date. For the vector-like singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations.

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables, including additional supplementary figures, can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/EXO-21-002 (CMS Public Pages)

References in corpus (32)

• 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
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm
• Particle-flow reconstruction and global event description with the CMS detector
• Pileup subtraction using jet areas
• The CMS trigger system
• The Catchment Area of Jets
• MCFM for the Tevatron and the LHC
• Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV
• Search for lepton-universality violation in $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Pileup Per Particle Identification
• Test of lepton universality in beauty-quark decays
• Low energy effects of neutrino masses
• Precision luminosity measurement in proton-proton collisions at $\sqrt{s}=$ 13 TeV in 2015 and 2016 at CMS
• Effects of new leptons in Electroweak Precision Data
• Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC
• Performance of missing transverse momentum reconstruction in proton-proton collisions at $\sqrt{s}=$ 13 TeV using the CMS detector
• Type-III see-saw at LHC
• The Leptoquark Hunter's Guide: Pair Production
• Limits on Vectorlike Leptons from Searches for Anomalous Production of Multi-Lepton Events
• Prospects for vectorlike leptons at future proton-proton colliders
• Search for singly and pair-produced leptoquarks coupling to third-generation fermions in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Model Building from Asymptotic Safety with Higgs and Flavor Portals
• Search for pair production of third-generation scalar leptoquarks decaying into a top quark and a $\tau$-lepton in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Search for pair production of scalar leptoquarks decaying into first- or second-generation leptons and top quarks in proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Resonant third-generation leptoquark signatures at the Large Hadron Collider
• Effects of vectorlike leptons on $h\to 4\ell$ and the connection to the muon g-2 anomaly
• Type-III Seesaw: Phenomenological Implications of the Information Lost in Decoupling from High-Energy to Low-Energy
• Type-III see-saw: Search for triplet fermions in final states with multiple leptons and fat-jets at 13 TeV LHC
• Composite Higgs and leptoquarks from a simple group
• Leptoquarks decaying to a top quark and a charged lepton at hadron colliders

Cited by in corpus (20)

• $W$ boson mass and muon $g-2$ in a lepton portal dark matter model
• The symmetry approach to quark and lepton masses and mixing
• Physics implications of recent Dresden-II reactor data
• New physics interpretation of $W$-boson mass anomaly
• Testing electroweak scale seesaw models at $e^{-}\gamma$ and $\gamma \gamma$ colliders
• Fresh look at the LHC limits on scalar leptoquarks
• W-mass Anomaly in the Simplest Linear Seesaw Mechanism
• Testing tree level TeV scale seesaw scenarios in $\mu$TRISTAN
• The Muon Magnetic Moment and Physics Beyond the Standard Model
• Current Status of the Muon g-2 Interpretations within Two-Higgs-Doublet Models
• Long-lived Searches of Vector-like Lepton and Its Accompanying Scalar at Colliders
• Stability of the Standard Model Vacuum with Vector-Like Leptons: A Critical Examination
• Mutually elusive: vectorlike antileptons and leptoquarks
• Muon $g-2$ Anomaly from Vector-like Leptons in a 2-Higgs-doublet + Scalar Singlet Model
• Semi-visible dark photon in a model with vector-like leptons for the $(g-2{)}_{e,\mu }$ and $W$-boson mass anomalies
• Collider imprint of vector-like leptons in light of anomalous magnetic moment and neutrino data
• Dirac Neutrinos and Dark Matter within a Minimal Discrete Symmetry Model
• Search for new physics in jet multiplicity patterns of multilepton events at $\sqrt{s}$ = 13 TeV
• Searches for New High-Mass Resonances Decaying to Fermions at the LHC
• Constraining the new contributions to electron $g-2$ in a radiative neutrino mass model