Measurement of the <i>W</i> boson polarization in top quark decays with the ATLAS detector
JOURNAL OF HIGH ENERGY PHYSICS, no.6, 2012 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Publication Date: 2012
- Doi Number: 10.1007/jhep06(2012)088
- Journal Name: JOURNAL OF HIGH ENERGY PHYSICS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Keywords: Hadron-Hadron Scattering
- Open Archive Collection: AVESIS Open Access Collection
- Ankara University Affiliated: Yes
Abstract
This paper presents measurements of the polarization of W bosons in top quark decays, derived from t (t) over bar 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.