Searches for scalar leptoquarks and differential cross-section measurements in dilepton-dijet events in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV with the ATLAS experiment

Abstract

Searches for scalar leptoquarks pair-produced in proton-proton collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider are performed by the ATLAS experiment. A data set corresponding to an integrated luminosity of 36.1 fb${}^{-1}$ is used. Final states containing two electrons or two muons and two or more jets are studied, as are states with one electron or muon, missing transverse momentum and two or more jets. No statistically significant excess above the Standard Model expectation is observed. The observed and expected lower limits on the leptoquark mass at 95% confidence level extend up to 1.29 TeV and 1.23 TeV for first- and second-generation leptoquarks, respectively, as postulated in the minimal Buchmüller-Rückl-Wyler model, assuming a branching ratio into a charged lepton and a quark of 50%. In addition, measurements of particle-level fiducial and differential cross sections are presented for the $Z\to ee$, $Z\to \mu \mu$ and $t\bar{t}$ processes in several regions related to the search control regions. Predictions from a range of generators are compared with the measurements, and good agreement is seen for many of the observables. However, the predictions for the $Z\to \ell \ell$ measurements in observables sensitive to jet energies disagree with the data.

62 pages in total, author list starting page 46, 19 figures, 5 tables, published in EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2016-08/

References in corpus (16)

• PYTHIA 6.4 Physics and Manual
• Parton distributions for the LHC
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• New parton distributions for collider physics
• Event generation with SHERPA 1.1
• Parton distributions in the LHC era: MMHT 2014 PDFs
• Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations
• Luminosity determination in pp collisions at $\sqrt{s}$ = 8 TeV using the ATLAS detector at the LHC
• HistFitter software framework for statistical data analysis
• Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data
• Search for new high-mass phenomena in the dilepton final state using 36 fb${}^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• The Leptoquark Hunter's Guide: Pair Production
• What is the scale of new physics behind the $B$-flavour anomalies?
• $B$ decay anomalies and dark matter from vectorlike confinement
• Searches for third-generation scalar leptoquarks in $\sqrt{s}$ = 13 TeV pp collisions with the ATLAS detector
• Search for second generation scalar leptoquarks in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

Cited by in corpus (32)

• Robust Independent Validation of Experiment and Theory: Rivet version 3
• Searches for physics beyond the standard model with the $M_{T2}$ variable in hadronic final states with and without disappearing tracks in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Search for pairs of scalar leptoquarks decaying into quarks and electrons or muons in $\sqrt{s}=13$ TeV pp collisions with the ATLAS detector
• Lepton-quark collisions at the Large Hadron Collider
• Precision predictions for scalar leptoquark pair-production at hadron colliders
• Searches for third-generation scalar leptoquarks in $\sqrt{s}$ = 13 TeV pp collisions with the ATLAS detector
• Search for singly and pair-produced leptoquarks coupling to third-generation fermions in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Searching for Leptoquarks at Future Muon Colliders
• Software and computing for Run 3 of the ATLAS experiment at the LHC
• Hunting scalar leptoquarks with boosted tops and light leptons
• A Common Origin of Neutrino Masses and $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$ Anomalies
• Testing new physics models with global comparisons to collider measurements: the Contur toolkit
• Enhancing Scalar Productions with Leptoquarks at the LHC
• New sensitivity of current LHC measurements to vector-like quarks
• Boosting vector leptoquark searches with boosted tops
• Scalar leptoquark pair production at the LHC: precision predictions in the era of flavour anomalies
• Distinguishing Leptoquarks at the LHC/FCC
• Precise probing and discrimination of third-generation scalar leptoquarks
• Constraints on scalar and vector leptoquarks from the LHC Higgs data
• The Muon Magnetic Moment and Physics Beyond the Standard Model
• High $p_T$ correlated tests of lepton universality in lepton(s) + jet(s) processes; an EFT analysis
• Search for excited electrons singly produced in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS experiment at the LHC
• Dark Matter from Anomaly Cancellation at the LHC
• Local Baryon Number at the LHC
• Revisiting the Scalar Leptoquark ($S_1$) Model with the Updated Leptonic Constraints
• Machine-Learning Performance on Higgs-Pair Production Associated with Dark Matter at the LHC
• The Hydrogen Mixing Portal, Its Origins, and Its Cosmological Effects
• Signatures of Supersymmetry in Neutrino Telescopes
• A Review of the Exceptional Supersymmetric Standard Model
• Determination of coupling patterns by parallel searches for ${\mu }^{-}\to e^{+}$ and ${\mu }^{-}\to e^{-}$ in muonic atoms
• The Neutrinoless Double Beta Decay in the Colored Zee-Babu Model
• Testing the $R_{D^{(\ast )}}$ Anomaly at the LHeC