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Title: Measurement of the top quark polarization and $$t\bar{t}$$ spin correlations using dilepton final states in proton-proton collisions at $$\sqrt{s}=$$ 13 TeV

Abstract

Measurements of the top quark polarization and top quark pair ($$\mathrm{t\bar{t}}$$) spin correlations are presented using events containing two oppositely charged leptons (e$^+$e$^-$, e$$^\pm\mu^\mp$$, or $$\mu^+\mu^-$$) produced in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were recorded by the CMS experiment at the LHC in 2016 and correspond to an integrated luminosity of 35.9 fb$$^{-1}$$. A set of parton-level normalized differential cross sections, sensitive to each of the independent coefficients of the spin-dependent parts of the $$\mathrm{t\bar{t}}$$ production density matrix, is measured for the first time at 13 TeV. The measured distributions and extracted coefficients are compared with standard model predictions from simulations at next-to-leading-order (NLO) accuracy in quantum chromodynamics (QCD), and from NLO QCD calculations including electroweak corrections. All measurements are found to be consistent with the expectations of the standard model. The normalized differential cross sections are used in fits to constrain the anomalous chromomagnetic and chromoelectric dipole moments of the top quark to -0.24 $$C_\text{tG}/\Lambda^{2} < $$ 0.07 TeV$$^{-2}$$ and -0.33 $$< C^{I}_\text{tG}/\Lambda^{2} < $$ 0.20 TeV$$^{-2}$$, respectively, at 95% confidence level.

Authors:
;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
CMS Collaboration
OSTI Identifier:
1557461
Report Number(s):
FERMILAB-PUB-19-417-CMS; arXiv:1907.03729; CMS-TOP-18-006; CERN-EP-2019-073
Journal ID: ISSN; 2470-0010; oai:inspirehep.net:1742786
Grant/Contract Number:  
AC02-07CH11359
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 100; Journal Issue: 7
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Sirunyan, Albert M, and et al. Measurement of the top quark polarization and $t\bar{t}$ spin correlations using dilepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV. United States: N. p., 2019. Web. doi:10.1103/PhysRevD.100.072002.
Sirunyan, Albert M, & et al. Measurement of the top quark polarization and $t\bar{t}$ spin correlations using dilepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV. United States. doi:10.1103/PhysRevD.100.072002.
Sirunyan, Albert M, and et al. Tue . "Measurement of the top quark polarization and $t\bar{t}$ spin correlations using dilepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV". United States. doi:10.1103/PhysRevD.100.072002. https://www.osti.gov/servlets/purl/1557461.
@article{osti_1557461,
title = {Measurement of the top quark polarization and $t\bar{t}$ spin correlations using dilepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV},
author = {Sirunyan, Albert M and et al.},
abstractNote = {Measurements of the top quark polarization and top quark pair ($\mathrm{t\bar{t}}$) spin correlations are presented using events containing two oppositely charged leptons (e$^+$e$^-$, e$^\pm\mu^\mp$, or $\mu^+\mu^-$) produced in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were recorded by the CMS experiment at the LHC in 2016 and correspond to an integrated luminosity of 35.9 fb$^{-1}$. A set of parton-level normalized differential cross sections, sensitive to each of the independent coefficients of the spin-dependent parts of the $\mathrm{t\bar{t}}$ production density matrix, is measured for the first time at 13 TeV. The measured distributions and extracted coefficients are compared with standard model predictions from simulations at next-to-leading-order (NLO) accuracy in quantum chromodynamics (QCD), and from NLO QCD calculations including electroweak corrections. All measurements are found to be consistent with the expectations of the standard model. The normalized differential cross sections are used in fits to constrain the anomalous chromomagnetic and chromoelectric dipole moments of the top quark to -0.24 $C_\text{tG}/\Lambda^{2} < $ 0.07 TeV$^{-2}$ and -0.33 $< C^{I}_\text{tG}/\Lambda^{2} < $ 0.20 TeV$^{-2}$, respectively, at 95% confidence level.},
doi = {10.1103/PhysRevD.100.072002},
journal = {Physical Review D},
number = 7,
volume = 100,
place = {United States},
year = {2019},
month = {10}
}

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Works referenced in this record:

Vector boson pair production at the LHC
journal, July 2011

  • Campbell, John M.; Ellis, R. Keith; Williams, Ciaran
  • Journal of High Energy Physics, Vol. 2011, Issue 7
  • DOI: 10.1007/JHEP07(2011)018

String formation beyond leading colour
journal, August 2015

  • Christiansen, Jesper R.; Skands, Peter Z.
  • Journal of High Energy Physics, Vol. 2015, Issue 8
  • DOI: 10.1007/JHEP08(2015)003

A positive-weight next-to-leading-order Monte Carlo for heavy flavour hadroproduction
journal, September 2007


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


Probing the top-quark chromomagnetic dipole moment at next-to-leading order in QCD
journal, June 2015


Non-resonant new physics in top pair production at hadron colliders
journal, March 2011

  • Degrande, Céline; Gérard, Jean-Marc; Grojean, Christophe
  • Journal of High Energy Physics, Vol. 2011, Issue 3
  • DOI: 10.1007/JHEP03(2011)125

Effects of color reconnection on tt¯ $$ t\overline{t} $$ final states at the LHC
journal, November 2014

  • Argyropoulos, Spyros; Sjöstrand, Torbjörn
  • Journal of High Energy Physics, Vol. 2014, Issue 11
  • DOI: 10.1007/JHEP11(2014)043

Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at √ s =13 TeV
journal, June 2018


A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX
journal, June 2010

  • Alioli, Simone; Nason, Paolo; Oleari, Carlo
  • Journal of High Energy Physics, Vol. 2010, Issue 6
  • DOI: 10.1007/JHEP06(2010)043

NNNLO soft-gluon corrections for the top-quark p T and rapidity distributions
journal, February 2015


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


Measurement of the Top Quark Pair Production Cross Section in Proton-Proton Collisions at s = 13 TeV
journal, February 2016


Measurement of the differential cross section for top quark pair production in pp collisions at $$\sqrt{s} = 8\,\text {TeV} $$ s = 8 TeV
journal, November 2015


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

FastJet user manual: (for version 3.0.2)
journal, March 2012


A general analysis of Wtb anomalous couplings
journal, June 2017


Parton distributions for the LHC run II
journal, April 2015

  • Ball, Richard D.; Bertone, Valerio; Carrazza, Stefano
  • Journal of High Energy Physics, Vol. 2015, Issue 4
  • DOI: 10.1007/JHEP04(2015)040

Measurement of the Drell-Yan cross section in pp collisions at $ \sqrt {s} = 7 $ TeV
journal, October 2011

  • Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.
  • Journal of High Energy Physics, Vol. 2011, Issue 10
  • DOI: 10.1007/JHEP10(2011)007

Higher Order Corrections to Spin Correlations in Top Quark Pair Production at the LHC
journal, August 2019


Review of Particle Physics
journal, August 2018


Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions
journal, December 2007


Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD
journal, May 2018

  • Czakon, Michal; Ferroglia, Andrea; Heymes, David
  • Journal of High Energy Physics, Vol. 2018, Issue 5
  • DOI: 10.1007/JHEP05(2018)149

Revised experimental upper limit on the electric dipole moment of the neutron
journal, November 2015


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


A new twist on top quark spin correlations
journal, March 2013

  • Baumgart, Matthew; Tweedie, Brock
  • Journal of High Energy Physics, Vol. 2013, Issue 3
  • DOI: 10.1007/JHEP03(2013)117

Two-loop soft anomalous dimensions for single top quark associated production with a W or H
journal, September 2010


Latest constraint on nonstandard top-gluon couplings at hadron colliders and its future prospect
journal, July 2013


Matching NLO QCD computations with parton shower simulations: the POWHEG method
journal, November 2007


Tuning PYTHIA 8.1: the Monash 2013 tune
journal, August 2014


The CMS experiment at the CERN LHC
journal, August 2008


Top-pair production at the LHC through NNLO QCD and NLO EW
journal, October 2017

  • Czakon, Michał; Heymes, David; Mitov, Alexander
  • Journal of High Energy Physics, Vol. 2017, Issue 10
  • DOI: 10.1007/JHEP10(2017)186

Merging meets matching in MC@NLO
journal, December 2012

  • Frederix, Rikkert; Frixione, Stefano
  • Journal of High Energy Physics, Vol. 2012, Issue 12
  • DOI: 10.1007/JHEP12(2012)061

Single-top Wt-channel production matched with parton showers using the POWHEG method
journal, February 2011


Unbiased global determination of parton distributions and their uncertainties at NNLO and at LO
journal, February 2012


Identification and filtering of uncharacteristic noise in the CMS hadron calorimeter
journal, March 2010


Chromomagnetic dipole moment of the top quark revisited
journal, November 2007


Bootstrap Methods: Another Look at the Jackknife
journal, January 1979


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


Rivet user manual
journal, December 2013

  • Buckley, Andy; Butterworth, Jonathan; Grellscheid, David
  • Computer Physics Communications, Vol. 184, Issue 12
  • DOI: 10.1016/j.cpc.2013.05.021

A New Method for Combining NLO QCD with Shower Monte Carlo Algorithms
journal, November 2004


Spin correlation effects in top quark pair production at the LHC
journal, April 2010


Measurement of the Inelastic Proton-Proton Cross Section at s = 13 TeV with the ATLAS Detector at the LHC
journal, October 2016


Combining QCD and electroweak corrections to dilepton production in the framework of the FEWZ simulation code
journal, November 2012


PDF4LHC recommendations for LHC Run II
journal, January 2016

  • Butterworth, Jon; Carrazza, Stefano; Cooper-Sarkar, Amanda
  • Journal of Physics G: Nuclear and Particle Physics, Vol. 43, Issue 2
  • DOI: 10.1088/0954-3899/43/2/023001

Measurements of t t ¯ Spin Correlations and Top-Quark Polarization Using Dilepton Final States in p p Collisions at s = 7 TeV
journal, May 2014


e + e − Production of heavy quarks in the string model
journal, June 1981

  • Bowler, M. G.
  • Zeitschrift für Physik C Particles and Fields, Vol. 11, Issue 2
  • DOI: 10.1007/BF01574001

Scaling violations in inclusive e + e annihilation spectra
journal, January 1983


Limits on anomalous top-quark gauge couplings from Tevatron and LHC data
journal, December 2014


Improved Experimental Limit on the Electric Dipole Moment of the Neutron
journal, September 2006


Top++: A program for the calculation of the top-pair cross-section at hadron colliders
journal, November 2014


LHC experimental sensitivity to CP violating gt   couplings
journal, February 2003


Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV
journal, May 2018


NLO single-top production matched with shower in POWHEG: s - and t -channel contributions
journal, September 2009


Top-quark pair production at hadron colliders: differential cross section and phenomenological applications with DiffTop
journal, January 2015

  • Guzzi, Marco; Lipka, Katerina; Moch, Sven-Olaf
  • Journal of High Energy Physics, Vol. 2015, Issue 1
  • DOI: 10.1007/JHEP01(2015)082

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

An introduction to PYTHIA 8.2
journal, June 2015

  • Sjöstrand, Torbjörn; Ask, Stefan; Christiansen, Jesper R.
  • Computer Physics Communications, Vol. 191
  • DOI: 10.1016/j.cpc.2015.01.024

A set of top quark spin correlation and polarization observables for the LHC: Standard Model predictions and new physics contributions
journal, December 2015

  • Bernreuther, Werner; Heisler, Dennis; Si, Zong-Guo
  • Journal of High Energy Physics, Vol. 2015, Issue 12
  • DOI: 10.1007/JHEP12(2015)026

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

Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations
journal, March 2013

  • Artoisenet, Pierre; Frederix, Rikkert; Mattelaer, Olivier
  • Journal of High Energy Physics, Vol. 2013, Issue 3
  • DOI: 10.1007/JHEP03(2013)015

Pinning down top dipole moments with ultraboosted tops
journal, May 2015

  • Aguilar-Saavedra, Juan A.; Fuks, Benjamin; Mangano, Michelangelo L.
  • Physical Review D, Vol. 91, Issue 9
  • DOI: 10.1103/PhysRevD.91.094021

The CMS trigger system
journal, January 2017


TUnfold, an algorithm for correcting migration effects in high energy physics
journal, October 2012


Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV
journal, February 2017


Associated production of a top-quark pair with vector bosons at NLO in QCD: impact on t t ¯ H $$ \mathrm{t}\overline{\mathrm{t}}\mathrm{H} $$ searches at the LHC
journal, February 2016

  • Maltoni, Fabio; Pagani, Davide; Tsinikos, Ioannis
  • Journal of High Energy Physics, Vol. 2016, Issue 2
  • DOI: 10.1007/JHEP02(2016)113

Distributions and correlations for top quark pair production and decay at the Tevatron and LHC
journal, September 2010


QCD-corrected spin analysing power of jets in decays of polarized top quarks
journal, July 2002


Particle-flow reconstruction and global event description with the CMS detector
journal, October 2017


Event generator tunes obtained from underlying event and multiparton scattering measurements
journal, March 2016