Measurement of top quark polarisation in t-channel single top quark production

Abstract

A first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 inverse-femtobarns. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. A differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26 +/- 0.03 (stat) +/- 0.10 (syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.

Replaced with published version. Added journal reference and DOI. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-13-001/index.html

References in corpus (17)

• PYTHIA 6.4 Physics and Manual
• 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
• 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
• MCFM for the Tevatron and the LHC
• Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
• FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order
• Measurement of the differential cross section for top quark pair production in pp collisions at sqrt(s) = 8 TeV
• Measurement of the single-top-quark t-channel cross section in pp collisions at sqrt(s) = 7 TeV
• Single top quark production at LHC with anomalous Wtb couplings
• Automating the POWHEG method in Sherpa
• Extended Parameterisations for MSTW PDFs and their effect on Lepton Charge Asymmetry from W Decays
• Anomalous Top Couplings at Hadron Colliders Revisited
• Differential and total cross sections for top pair and single top production

Cited by in corpus (21)

• Cross section measurement of t-channel single top quark production in pp collisions at sqrt(s) = 13 TeV
• Search for anomalous Wtb couplings and flavour-changing neutral currents in t-channel single top quark production in pp collisions at sqrt(s) = 7 and 8 TeV
• Single top-quark production at the Tevatron and the LHC
• CP-violation for Electroweak Baryogenesis from Dynamical CKM Matrix
• Breaking down the entire spectrum of spin correlations of a pair of particles involving fermions and gauge bosons
• Top-Quark Physics: Status and Prospects
• Probing the $Wtb$ vertex structure in $t$-channel single-top-quark production and decay in $pp$ collisions at $\sqrt{\mathrm{s}}=8$ TeV with the ATLAS detector
• Measurement of differential cross sections and charge ratios for $t$-channel single top quark production in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Top-quark physics at the Large Hadron Collider
• Analysis of the $Wtb$ vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the $t$-channel at $\sqrt{s}$ = 8 TeV with the ATLAS detector
• Inclusive and differential cross section measurements of single top quark production in association with a Z boson in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Non-factorisable contribution to $t$-channel single-top production
• Search for supersymmetry in events with one lepton and multiple jets exploiting the angular correlation between the lepton and the missing transverse momentum in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• MINLO t-channel single-top plus jet
• Single Top Quark Production with and without a Higgs Boson
• $T$-odd correlations in polarized top quark decays in the sequential decay $t(\uparrow )\to X_b+W^{+}(\to {\ell }^{+}+{\nu }_{\ell })$ and in the quasi three-body decay $t(\uparrow )\to X_b+{\ell }^{+}+{\nu }_{\ell }$
• Higher spin swampland conjecture for massive AdS${}_3$ gravity
• $O({\alpha }_s)$ perturbative and nonperturbative corrections to polarized semileptonic ${\Lambda }_b$ decay distributions
• Single-top production and rare top interactions
• Top quark properties measurements at the LHC
• Measuring quark polarizations at ATLAS and CMS