Browsing by Author "Acharyaa B. S."
Measurement of the polarisation of Wbosons produced in top-quark decays using dilepton events at ?s=13TeV with the ATLAS experiment
(ELSEVIER, 2023/08/10) Aad G.; Abbott B.; Abbott D. C.; Abeling K.; Abidi S. H.; Aboulhormae A.; Abramowicz H.; Abreu H.; Abulaiti Y.; Abusleme Hoffmana A. C.; Acharyaa B. S.; Bourdarios C. Adam; Adamczyka L.; Adamek L.; Addepalli S. V.; Adelman J.; Adiguzelc A.; Adorni S.; Adye T.; Affolder A. A.; Afik Y.; Agaras M. N.; Agarwalaa J.; Aggarwal A.; Agheorghieseic C.; Aguilar-Saavedraf J. A.; Ahmad A.; Ahmadov F.; Ahmed W. S.; Ahuja S.; Ai X.; Aiellia G.; Tamlihate M. Ait; Aitbenchikh B.; Aizenberg I.; Akbiyik M.; Akesson T. P. A.; Akimov A. V.; Al Khoury K.; Alberghib G. L.
A measurement of the polarisation of Wbosons produced in top-quark decays is presented, using proton-proton collision data at a centre-of-mass energy of v s= 13TeV. The data were collected by the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 139fb(-1). The measurement is performed selecting t tevents decaying into final states with two charged leptons (electrons or muons) and at least two b-tagged jets. The polarisation is extracted from the differential cross-section distribution of the cos theta* variable, where theta(*) is the angle between the momentum direction of the charged lepton from the Wboson decay and the reversed momentum direction of the b-quark from the top-quark decay, both calculated in the Wboson rest frame. Parton-level results, corrected for the detector acceptance and resolution, are presented for the cos theta* angle. The measured fractions of longitudinal, left- and right-handed polarisation states are found to be f(0) = 0.684 +/- 0.005 (stat.)+/- 0.014 (syst.), f(L)= 0.318 +/- 0.003 (stat.)+/- 0.008 (syst.) and f(R)=-0.002 +/- 0.002 (stat.)+/- 0.014 (syst.), in agreement with the Standard Model prediction. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).