Search for vector-like $B$ quarks in events with one isolated lepton, missing transverse momentum and jets at $\sqrt{s}=$ 8 TeV with the ATLAS detector

Abstract

A search has been performed for pair production of heavy vector-like down-type ($B$) quarks. The analysis explores the lepton-plus-jets final state, characterized by events with one isolated charged lepton (electron or muon), significant missing transverse momentum and multiple jets. One or more jets are required to be tagged as arising from $b$-quarks, and at least one pair of jets must be tagged as arising from the hadronic decay of an electroweak boson. The analysis uses the full data sample of $pp$ collisions recorded in 2012 by the ATLAS detector at the LHC, operating at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb${}^{-1}$. No significant excess of events is observed above the expected background. Limits are set on vector-like $B$ production, as a function of the $B$ branching ratios, assuming the allowable decay modes are $B\to Wt/Zb/Hb$. In the chiral limit with a branching ratio of 100% for the decay $B\to Wt$, the observed (expected) 95% CL lower limit on the vector-like $B$ mass is 810 GeV (760 GeV). In the case where the vector-like $B$ quark has branching ratio values corresponding to those of an $SU(2)$ singlet state, the observed (expected) 95% CL lower limit on the vector-like $B$ mass is 640 GeV (505 GeV). The same analysis, when used to investigate pair production of a colored, charge 5/3 exotic fermion $T_{5/3}$, with subsequent decay $T_{5/3}\to Wt$, sets an observed (expected) 95% CL lower limit on the $T_{5/3}$ mass of 840 GeV (780 GeV).

28 pages plus author list + cover pages (44 pages total), 11 figures, 5 tables, published version, all figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2014-17/

References in corpus (34)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• PYTHIA 6.4 Physics and Manual
• Parton distributions for the LHC
• New parton distributions for collider physics
• Event generation with SHERPA 1.1
• Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions
• Vector boson pair production at the LHC
• Two-loop soft anomalous dimensions for single top quark associated production with a W- or H-
• FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order
• Light custodians in natural composite Higgs models
• Next-to-next-to-leading-order collinear and soft gluon corrections for t-channel single top quark production
• NNLL resummation for s-channel single top quark production
• Jet energy measurement and its systematic uncertainty in proton-proton collisions at $\sqrt{s}=7$ TeV with the ATLAS detector
• Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton-proton collision data
• Precise Predictions for W + 4 Jet Production at the Large Hadron Collider
• t tbar W and t tbar Z Hadroproduction at NLO accuracy in QCD with Parton Shower and Hadronization effects
• Search for the Standard Model Higgs boson produced in association with top quarks and decaying into $b\bar{b}$ in pp collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector
• Single top quark production at LHC with anomalous Wtb couplings
• Measurement of the charge asymmetry in top quark pair production in pp collisions at sqrt(s) = 7 TeV using the ATLAS detector
• High transverse momentum quarkonium production and dissociation in heavy ion collisions
• Observation of Single Top Quark Production and Measurement of |Vtb| with CDF
• Search for top-quark partners with charge 5/3 in the same-sign dilepton final state
• Search for pair and single production of new heavy quarks that decay to a $Z$ boson and a third-generation quark in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Theory and Phenomenology of Exotic Isosinglet Quarks and Squarks
• Heavy Quarks Above the Top at the Tevatron
• Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton-proton collisions at $\sqrt{s}$=7 TeV in 2010
• Stabilizing Electroweak Vacuum in a Vector-like Fermion Model
• Measurement of the production cross section of prompt J/psi mesons in association with a W boson in pp collisions at sqrt{s}=7 TeV with the ATLAS detector
• Constraints on the Four-Generation Quark Mixing Matrix from a Fit to Flavor-Physics Data
• Vector-like Bottom Quarks in Composite Higgs Models
• Unification of Gauge Couplings in the Standard Model with Extra Vector-like Families
• Search for heavy quarks decaying into a top quark and a W or Z boson using lepton + jets events in pp collisions at sqrt(s) = 7 TeV
• Higgs data confronts Sequential Fourth Generation Fermions in the Higgs Triplet Model

Cited by in corpus (60)

• From the trees to the forest: a review of radiative neutrino mass models
• What is the gamma gamma resonance at 750 GeV?
• Rays of light from the LHC
• Search for production of vector-like quark pairs and of four top quarks in the lepton-plus-jets final state in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• A Model of Visible QCD Axion
• Bounding wide composite vector resonances at the LHC
• New Vector-Like Fermions and Flavor Physics
• The Minimal Scalar-Stealth Top Interpretation of the Diphoton Excess
• Indirect Constraints on the Scalar Di-Photon Resonance at the LHC
• Vector-like Fermions and Higgs Effective Field Theory Revisited
• Direct and indirect signals of natural composite Higgs models
• Scalar Explanation of Diphoton Excess at LHC
• Search for pair production of a new heavy quark that decays into a $W$ boson and a light quark in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Electroweak Vacuum Stability and Diphoton Excess at 750 GeV
• Novel signatures for vector-like quarks
• Search for single production of a vector-like T quark decaying to a Z boson and a top quark in proton-proton collisions at $\sqrt{s}=$13 TeV
• Search for single production of vector-like quarks decaying to a top quark and a W boson in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Fermionic extensions of the Standard Model in light of the Higgs couplings
• Search for pair production of vector-like T and B quarks in single-lepton final states using boosted jet substructure in proton-proton collisions at sqrt(s) = 13 TeV
• Standard Model Effective Field Theory: Integrating out Vector-Like Fermions
• Signs of Composite Higgs Pair Production at Next-to-Leading Order
• A Loop-philic Pseudoscalar
• Vector-like top/bottom quark partners and Higgs physics at the LHC
• Search for single production of vector-like quarks decaying to a b quark and a Higgs boson
• Search for the production of single vector-like and excited quarks in the $Wt$ final state in $pp$ collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector
• Search for single production of vector-like quarks decaying into a b quark and a W boson in proton-proton collisions at sqrt(s) = 13 TeV
• Novel Interpretation Strategy for Searches of Singly Produced Vector-like Quarks at the LHC
• Interpretation of Vector-like Quark Searches: Heavy Gluons in Composite Higgs Models
• Future Collider Signatures of the Possible 750 GeV State
• Interpreting The 750 GeV Diphoton Excess Within Topflavor Seesaw Model
• Tadpole-Induced Electroweak Symmetry Breaking and pNGB Higgs Models
• Exotic Signals of Vectorlike Quarks
• Search for single production of vector-like quarks decaying to a Z boson and a top or a bottom quark in proton-proton collisions at sqrt(s) = 13 TeV
• Search for top quark partners with charge 5/3 in the same-sign dilepton and single-lepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Threshold enhancement of diphoton resonances
• Search for single production of a vector-like quark via a heavy gluon in the $4b$ final state with the ATLAS detector in $pp$ collisions at $\sqrt{s}=8$ TeV
• The $W\gamma$ decay of the elusive charged Higgs boson in the two-Higgs-doublet model with vectorlike fermions
• Searching for signatures of $E_6$
• Electroweak symmetry breaking and collider signatures in the next-to-minimal composite Higgs model
• Disentangling new physics effects on non-resonant Higgs boson pair production from gluon fusion
• Vector-like Quarks at the Origin of Light Quark Masses and Mixing
• The Top Quark
• A 2 TeV $W_R$, Supersymmetry, and the Higgs Mass
• Vacuum stability in the Standard Model with vector-like fermions
• 750 GeV Diphotons and Supersymmetric Grand Unification
• Search for singly produced vector-like top partners in multilepton final states with 139 ${\mathrm{fb}}^{-1}$ of $pp$ collision data at $\sqrt{s}=13$ TeV with the ATLAS detector
• The 750 GeV diphoton excess in a two Higgs doublet model and a singlet scalar model, with vector-like fermions, unitarity constraints, and dark matter implications
• Single production of $X_{\pm 5/3}$ and $Y_{\mp 4/3}$ vectorlike quarks at the LHC
• Direct Constraints, Flavor Physics, and Flavor Anomalies in Composite Higgs Models
• Search for top quark partners with charge 5/3 in proton-proton collisions at sqrt(s) = 13 TeV
• Same sign di-lepton candles of the composite gluons
• From the 750 GeV Diphoton Resonance to Multilepton Excesses
• Exotic colored scalars at the LHC
• Top and bottom partners, Higgs boson on the brane, and the tth signal
• Constraints from Triple Gauge Couplings on Vectorlike Leptons
• Pair Production of Beyond the Standard Model Higgs Bosons
• Spontaneous CP Violation and the Strong CP Problem in Left-Right Symmetric Theories
• Exotic Decays of Heavy B quarks
• Direct Search Implications for a Custodially-Embedded Composite Top
• Asymmetric Dark Matter in Extended Exo-Higgs Scenarios