Measurement of the W boson polarization in top quark decays with the ATLAS detector

Abstract

This paper presents measurements of the polarization of W bosons in top quark decays, derived from ttbar events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data from pp collisions at a centre-of-mass energy of 7 TeV were collected with the ATLAS experiment at the LHC and correspond to an integrated luminosity of 1.04 fb^-1. The measured fractions of longitudinally, left- and right-handed polarization are F_0=0.67+/-0.07, F_L=0.32+/-0.04 and F_R=0.01+/-0.05, in agreement with the Standard Model predictions. As the polarization of the W bosons in top quark decays is sensitive to the Wtb vertex Lorentz structure and couplings, the measurements were used to set limits on anomalous contributions to the Wtb couplings.

24 pages plus author list (47 pages total), 7 figures, 4 tables, submitted to JHEP

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Cited by in corpus (14)

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• Measurement of the W boson helicity in events with a single reconstructed top quark in pp collisions at sqrt(s) = 8 TeV
• New directions for top quark polarization in the $t$-channel process
• Studying the $Wtb$ vertex structure using recent LHC results
• Search for supersymmetry in events with b-quark jets and missing transverse energy in pp collisions at 7 TeV
• Anomalous Top Couplings at Hadron Colliders Revisited
• Measurement of W-Boson Polarization in Top-quark Decay using the Full CDF Run II Data Set
• 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
• Pseudoscalar couplings in $t\bar{t}H$ production at NLO+NLL accuracy
• Anomalous top charged-current contact interactions in single top production at the LHC
• Top quark physics in the Large Hadron Collider era
• Study of Top Effective Operators at the ILC
• Top Decays in the Standard Model and Beyond
• Searches for new physics in top decays at the LHC