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Title: Observation of top quark pairs produced in association with a vector boson in pp collisions at √(s) = 8 TeV

Abstract

Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 fb-1, collected by the CMS experiment at the LHC. We found that final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from tt-W or tt-Z decays. The tt-W cross section is measured to be 382+117 -102 fb with a significance of 4.8 standard deviations from the background-only hypothesis. The tt-Z cross section is measured to be 242+65 -55 fb with a significance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on five anomalous dimension-six operators that would affect the tt-W and tt-Z cross sections.

Authors:
 [1]
  1. Yerevan Physics Inst. (YerPhI) (Armenia). et al.
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP)
Contributing Org.:
CMS Collaboration; CMS
OSTI Identifier:
1226331
Alternate Identifier(s):
OSTI ID: 1334975
Report Number(s):
FERMILAB-PUB-15-468-CMS; FERMILAB-PUB-16-586-CMS; CMS-SMP-14-013; CERN-EP-2016-256; arXiv:1611.03844
Journal ID: ISSN 1029-8479; arXiv eprint number arXiv:1510.01131
Grant/Contract Number:  
AC02-07CH11359
Resource Type:
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2016; Journal Issue: 96; Journal ID: ISSN 1029-8479
Publisher:
Springer Berlin
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Khachatryan, Vardan. Observation of top quark pairs produced in association with a vector boson in pp collisions at √(s) = 8 TeV. United States: N. p., 2016. Web. doi:10.1007/JHEP01(2016)096.
Khachatryan, Vardan. Observation of top quark pairs produced in association with a vector boson in pp collisions at √(s) = 8 TeV. United States. doi:10.1007/JHEP01(2016)096.
Khachatryan, Vardan. Mon . "Observation of top quark pairs produced in association with a vector boson in pp collisions at √(s) = 8 TeV". United States. doi:10.1007/JHEP01(2016)096. https://www.osti.gov/servlets/purl/1226331.
@article{osti_1226331,
title = {Observation of top quark pairs produced in association with a vector boson in pp collisions at √(s) = 8 TeV},
author = {Khachatryan, Vardan},
abstractNote = {Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 fb-1, collected by the CMS experiment at the LHC. We found that final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from tt-W or tt-Z decays. The tt-W cross section is measured to be 382+117 -102 fb with a significance of 4.8 standard deviations from the background-only hypothesis. The tt-Z cross section is measured to be 242+65 -55 fb with a significance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on five anomalous dimension-six operators that would affect the tt-W and tt-Z cross sections.},
doi = {10.1007/JHEP01(2016)096},
journal = {Journal of High Energy Physics (Online)},
number = 96,
volume = 2016,
place = {United States},
year = {2016},
month = {1}
}

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Works referenced in this record:

The anti- k t jet clustering algorithm
journal, April 2008


Measurement of top quark–antiquark pair production in association with a W or Z boson in pp collisions at $$\sqrt{s} = 8$$ s = 8 $$\,\text {TeV}$$ TeV
journal, September 2014


A precise measurement of the partial decay width ratio ${R_{\mathrm{b}}}^0 = \Gamma_{\mathrm{b\bar{b}}}/\Gamma_{\mathrm{had}}$
journal, October 1999


Review of Particle Physics
journal, August 2014


A study of ${\mathrm{b}}\bar{\mathrm{b}}$ production in e+e− collisions at $\sqrt{s}=130$ –207 GeV
journal, February 2009


Identification of b-quark jets with the CMS experiment
journal, April 2013


Phenomenology of the Higgs effective Lagrangian via FeynRules
journal, April 2014

  • Alloul, Adam; Fuks, Benjamin; Sanz, Verónica
  • Journal of High Energy Physics, Vol. 2014, Issue 4
  • DOI: 10.1007/JHEP04(2014)110

PYTHIA 6.4 physics and manual
journal, May 2006


Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
journal, September 2012


Complete Higgs sector constraints on dimension-6 operators
journal, July 2014

  • Ellis, John; Sanz, Verónica; You, Tevong
  • Journal of High Energy Physics, Vol. 2014, Issue 7
  • DOI: 10.1007/JHEP07(2014)036

The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
journal, July 2014

  • Alwall, J.; Frederix, R.; Frixione, S.
  • Journal of High Energy Physics, Vol. 2014, Issue 7
  • DOI: 10.1007/JHEP07(2014)079

Measurement of differential top-quark-pair production cross sections in pp collisions at $\sqrt{s} = 7\ \mathrm{TeV}$
journal, March 2013


Performance of CMS muon reconstruction in pp collision events at √s = 7 TeV
journal, October 2012


Dispelling the <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msup><mml:mi>N</mml:mi><mml:mn>3</mml:mn></mml:msup></mml:math> myth for the <mml:math altimg="si2.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msub><mml:mi>k</mml:mi><mml:mi>t</mml:mi></mml:msub></mml:math> jet-finder
journal, September 2006


A measurement of Rb using a lifetime-mass tag
journal, May 1997


Total Top-Quark Pair-Production Cross Section at Hadron Colliders Through O ( α S 4 )
journal, June 2013


FeynRules  2.0 — A complete toolbox for tree-level phenomenology
journal, August 2014

  • Alloul, Adam; Christensen, Neil D.; Degrande, Céline
  • Computer Physics Communications, Vol. 185, Issue 8
  • DOI: 10.1016/j.cpc.2014.04.012

New Generation of Parton Distributions with Uncertainties from Global QCD Analysis
journal, July 2002


t $ \bar{\mathrm{t}} $ W± + t $ \bar{\mathrm{t}} $ Z hadroproduction at NLO accuracy in QCD with Parton Shower and Hadronization effects
journal, November 2012

  • Garzelli, M. V.; Kardos, A.; Papadopoulos, C. G.
  • Journal of High Energy Physics, Vol. 2012, Issue 11
  • DOI: 10.1007/JHEP11(2012)056

Determination of jet energy calibration and transverse momentum resolution in CMS
journal, November 2011


The catchment area of jets
journal, April 2008


Effective lagrangian analysis of new interactions and flavour conservation
journal, May 1986


NLO QCD corrections to $$ {\text{t}}\overline {\text{t}} {\text{b}}\overline {\text{b}} $$ production at the LHC: 2. Full hadronic results
journal, March 2010

  • Bredenstein, A.; Denner, A.; Dittmaier, S.
  • Journal of High Energy Physics, Vol. 2010, Issue 3
  • DOI: 10.1007/JHEP03(2010)021

MCFM for the Tevatron and the LHC
journal, August 2010


Constraining couplings of top quarks to the Z boson in t t ¯ $$ t\overline{t} $$ + Z production at the LHC
journal, July 2014


Measurement of the inelastic proton–proton cross section at <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd" xmlns:sa="http://www.elsevier.com/xml/common/struct-aff/dtd"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>7</mml:mn><mml:mtext> TeV</mml:mtext></mml:math>
journal, May 2013


Measurement of the branching ratios of the Z 0 into heavy quarks
journal, June 2005


Dimension-six terms in the Standard Model Lagrangian
journal, October 2010

  • Grzadkowski, B.; Iskrzyński, M.; Misiak, M.
  • Journal of High Energy Physics, Vol. 2010, Issue 10
  • DOI: 10.1007/JHEP10(2010)085

Measurement of associated production of vector bosons and top quark-antiquark pairs in p p collisions at s = 7 TeV
journal, April 2013


A measurement of $R_{\rm b}$ using a double tagging method
journal, April 1999


Pileup subtraction using jet areas
journal, January 2008


Geant4—a simulation toolkit
journal, July 2003

  • Agostinelli, S.; Allison, J.; Amako, K.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 506, Issue 3
  • DOI: 10.1016/S0168-9002(03)01368-8

Asymptotic formulae for likelihood-based tests of new physics
journal, February 2011


FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order
journal, November 2011


NNLL threshold resummation for top-pair and single-top production
journal, July 2014


$$ t\overline t {W^{\pm }} $$ production and decay at NLO
journal, July 2012

  • Campbell, John M.; Ellis, R. Keith
  • Journal of High Energy Physics, Vol. 2012, Issue 7
  • DOI: 10.1007/JHEP07(2012)052

Boosted decision trees as an alternative to artificial neural networks for particle identification
journal, May 2005

  • Roe, Byron P.; Yang, Hai-Jun; Zhu, Ji
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 543, Issue 2-3
  • DOI: 10.1016/j.nima.2004.12.018

    Works referencing / citing this record:

    Search for supersymmetry in multijet events with missing transverse momentum in proton-proton collisions at 13 TeV
    journal, August 2017


    Measurements of t t ¯ spin correlations and top quark polarization using dilepton final states in p p collisions at s = 8 TeV
    journal, March 2016


    Search for supersymmetry in multijet events with missing transverse momentum in proton-proton collisions at 13 TeV
    journal, August 2017


    Searches for pair production of third-generation squarks in $$\sqrt{s}=13$$ s = 13 $$\,\text {TeV}$$ TeV pp collisions
    journal, May 2017


    Measurements of t t ¯ spin correlations and top quark polarization using dilepton final states in p p collisions at s = 8 TeV
    journal, March 2016


    Searches for pair production of third-generation squarks in $$\sqrt{s}=13$$ s = 13 $$\,\text {TeV}$$ TeV pp collisions
    journal, May 2017


    Top-quark physics at the Large Hadron Collider
    journal, May 2017


    Prompt J / ψ production in association with a top quark pair at the LHC
    journal, October 2019


    Pinning down electroweak dipole operators of the top quark
    journal, August 2016