@misc{10481/78425,
year = {2022},
month = {11},
url = {https://hdl.handle.net/10481/78425},
abstract = {A simultaneous measurement of the three components of the top-quark and top-antiquark polarisation vectors in t-channel single-top-quark production is presented. This analysis is based on data from proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb(-1), collected with the ATLAS detector at the LHC. Selected events contain exactly one isolated electron or muon, large missing transverse momentum and exactly two jets, one being b-tagged. Stringent selection requirements are applied to discriminate t-channel single-top-quark events from the background contributions. The top-quark and top-antiquark polarisation vectors are measured from the distributions of the direction cosines of the charged-lepton momentum in the top-quark rest frame. The three components of the polarisation vector for the selected top-quark event sample are P-x' = 0.01 +/- 0.18, P-y' = -0.029 +/- 0.027, P-z' = 0.91 +/- 0.10 and for the top-antiquark event sample they are P-x' = -0.02 +/- 0.20, P-y' = -0.007 +/- 0.051, P-z' = -0.79 +/- 0.16. Normalised differential cross-sections corrected to a fiducial region at the stable-particle level are presented as a function of the charged-lepton angles for top-quark and top-antiquark events inclusively and separately. These measurements are in agreement with Standard Model predictions. The angular differential cross-sections are used to derive bounds on the complex Wilson coefficient of the dimension-six O-tW operator in the framework of an effective field theory. The obtained bounds are C-tW is an element of[-0.9, 1.4] and C-itW is an element of [-0.8, 0.2], both at 95% confidence level.},
organization = {ANPCyT, Argentina},
organization = {YerPhI, Armenia},
organization = {ARC, Australia},
organization = {BMWFW and FWF, Austria},
organization = {ANAS, Azerbaijan},
organization = {SSTC, Belarus},
organization = {CNPq and
FAPESP, Brazil},
organization = {NSERC, NRC and CFI, Canada},
organization = {CERN},
organization = {ANID, Chile},
organization = {CAS, MOST and
NSFC, China},
organization = {Minciencias, Colombia},
organization = {MEYS CR, Czech Republic},
organization = {DNRF and DNSRC,
Denmark},
organization = {IN2P3-CNRS and CEA-DRF/IRFU, France},
organization = {SRNSFG, Georgia},
organization = {BMBF, HGF
and MPG, Germany},
organization = {GSRI, Greece},
organization = {RGC and Hong Kong SAR, China},
organization = {ISF and Benoziyo
Center, Israel},
organization = {INFN, Italy},
organization = {MEXT and JSPS, Japan},
organization = {CNRST, Morocco},
organization = {NWO, Netherlands},
organization = {RCN, Norway},
organization = {MEiN, Poland},
organization = {FCT, Portuga},
organization = {MNE/IFA, Romania},
organization = {JINR},
organization = {MES
of Russia and NRC KI, Russian Federation},
organization = {MESTD, Serbia},
organization = {MSSR, Slovakia},
organization = {ARRS and
MIZŠ, Slovenia},
organization = {DSI/NRF, South Africa},
organization = {MICINN, Spain},
organization = {SRC and Wallenberg Foundation,
Sweden},
organization = {SERI, SNSF and Cantons of Bern and Geneva, Switzerland},
organization = {MOST,
Taiwan},
organization = {TAEK, Turkey},
organization = {STFC, United Kingdom},
organization = {DOE and NSF, United States of America},
organization = {BCKDF,
CANARIE, Compute Canada and CRC, Canada},
organization = {COST, ERC, ERDF, Horizon 2020 and
Marie Skłodowska-Curie Actions, European Union},
organization = {Investissements d’Avenir Labex, Investissements
d’Avenir Idex and ANR, France},
organization = {DFG and AvH Foundation, Germany},
organization = {Herakleitos,
Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF,
Greece},
organization = {BSF-NSF and GIF, Israel},
organization = {Norwegian Financial Mechanism 2014-2021, Norway},
organization = {NCN and NAWA, Poland},
organization = {La Caixa Banking Foundation, CERCA Programme Generalitat
de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain},
organization = {Göran Gustafssons Stiftelse, Sweden},
organization = {The Royal Society and Leverhulme Trust, United
Kingdom},
publisher = {Springer},
keywords = {Hadron-Hadron scattering},
keywords = {Top physics},
title = {Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at s√
= 13 TeV and bounds on the tWb dipole operator from the ATLAS experiment},
doi = {10.1007/JHEP11(2022)040},
author = {Aad, G. and Aguilar Saavedra, Juan Antonio and Rodríguez Chala, Mikael and Atlas Collaboration},
}