The combination of measurements of the W boson polarization in top quark decays performed by the ATLAS and CMS collaborations is presented. The measurements are based on proton-proton collision data produced at the LHC at a centre-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of about 20 fb−1 for each experiment. The measurements used events containing one lepton and having different jet multiplicities in the final state. The results are quoted as fractions of W bosons with longitudinal (F0), left-handed (FL), or right-handed (FR) polarizations. The resulting combined measurements of the polarization fractions are F0 = 0.693 ± 0.014 and FL = 0.315 ± 0.011. The fraction FR is calculated from the unitarity constraint to be FR = −0.008 ± 0.007. These results are in agreement with the standard model predictions at next-to-next-to-leading order in perturbative quantum chromodynamics and represent an improvement in precision of 25 (29)% for F0 (FL) with respect to the most precise single measurement. A limit on anomalous right-handed vector (VR), and left- and right-handed tensor (gL, gR) tWb couplings is set while fixing all others to their standard model values. The allowed regions are [−0.11, 0.16] for VR, [−0.08, 0.05] for gL, and [−0.04, 0.02] for gR, at 95% confidence level. Limits on the corresponding Wilson coefficients are also derived.

Aad G., A.B. (2020). Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at √s = 8 TeV. JOURNAL OF HIGH ENERGY PHYSICS, 2020(8), 1-66 [10.1007/JHEP08(2020)051].

Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at √s = 8 TeV

Alberghi G. L.;Alfonsi A.;Alfonsi F.;Bellagamba L.;Bindi M.;Boscherini D.;Cabras G.;Caforio D.;De Castro S.;Di Sipio R.;Fabbri F.;Fabbri L.;Franchini M.;Gabrielli A.;Giacobbe B.;Lasagni Manghi F.;Macchiolo A.;Massa L.;Monzani S.;Polini A.;Rinaldi L.;Romano M.;Sbarra C.;Sbrizzi A.;Semprini-Cesari N.;Sioli M.;Todome K.;Ucchielli G.;Valentinetti S.;Villa M.;Vittori C.;Vivarelli I.;Zoccoli A.;Chhibra S. S.;Sharma A.;Battilana C.;Bonacorsi D.;Braibant-Giacomelli S.;Capiluppi P.;Codispoti G.;Fanfani A.;Guiducci L.;Iemmi F.;Marcellini S.;Navarria F. L.;Rovelli T.;Siroli G. P.;Fasanella D.;Sharma A.;
2020

Abstract

The combination of measurements of the W boson polarization in top quark decays performed by the ATLAS and CMS collaborations is presented. The measurements are based on proton-proton collision data produced at the LHC at a centre-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of about 20 fb−1 for each experiment. The measurements used events containing one lepton and having different jet multiplicities in the final state. The results are quoted as fractions of W bosons with longitudinal (F0), left-handed (FL), or right-handed (FR) polarizations. The resulting combined measurements of the polarization fractions are F0 = 0.693 ± 0.014 and FL = 0.315 ± 0.011. The fraction FR is calculated from the unitarity constraint to be FR = −0.008 ± 0.007. These results are in agreement with the standard model predictions at next-to-next-to-leading order in perturbative quantum chromodynamics and represent an improvement in precision of 25 (29)% for F0 (FL) with respect to the most precise single measurement. A limit on anomalous right-handed vector (VR), and left- and right-handed tensor (gL, gR) tWb couplings is set while fixing all others to their standard model values. The allowed regions are [−0.11, 0.16] for VR, [−0.08, 0.05] for gL, and [−0.04, 0.02] for gR, at 95% confidence level. Limits on the corresponding Wilson coefficients are also derived.
2020
Aad G., A.B. (2020). Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at √s = 8 TeV. JOURNAL OF HIGH ENERGY PHYSICS, 2020(8), 1-66 [10.1007/JHEP08(2020)051].
Aad G., Abbott B., Abbott D.C., Abed Abud A., Abeling K., Abhayasinghe D.K., Abidi S.H., Abou Zeid O.S., Abraham N.L., Abramowicz H., Abreu H., Abulai...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/803500
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