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
Articolo
Data di Pubblicazione:
2022
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 Px′ = 0.01 ± 0.18, Py′ = −0.029 ± 0.027, Pz′ = 0.91 ± 0.10 and for the top-antiquark event sample they are Px′ = −0.02 ± 0.20, Py′ = −0.007 ± 0.051, Pz′ = 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 OtW operator in the framework of an effective field theory. The obtained bounds are CtW ∈ [−0.9, 1.4] and CitW ∈ [−0.8, 0.2], both at 95% confidence level. [Figure not available: see fulltext.].
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
Hadron-Hadron Scattering; Top Physics
Elenco autori:
Aad G.; Abbott B.; Abbott D.C.; Abed Abud A.; Abeling K.; Abhayasinghe D.K.; Abidi S.H.; Abramowicz H.; Abreu H.; Abulaiti Y.; Abusleme Hoffman A.C.; Acharya B.S.; Achkar B.; Adam L.; Adam Bourdarios C.; Adamczyk L.; Adamek L.; Addepalli S.V.; Adelman J.; Adiguzel A.; Adorni S.; Adye T.; Affolder A.A.; Afik Y.; Agapopoulou C.; Agaras M.N.; Agarwala J.; Aggarwal A.; Agheorghiesei C.; Aguilar-Saavedra J.A.; Ahmad A.; Ahmadov F.; Ahmed W.S.; Ai X.; Aielli G.; Aizenberg I.; Akatsuka S.; Akbiyik M.; Akesson T.P.A.; Akimov A.V.; Al Khoury K.; Alberghi G.L.; Albert J.; Albicocco P.; Alconada Verzini M.J.; Alderweireldt S.; Aleksa M.; Aleksandrov I.N.; Alexa C.; Alexopoulos T.; Alfonsi A.; Alfonsi F.; Alhroob M.; Ali B.; Ali S.; Aliev M.; Alimonti G.; Allaire C.; Allbrooke B.M.M.; Allport P.P.; Aloisio A.; Alonso F.; Alpigiani C.; Alunno Camelia E.; Alvarez Estevez M.; Alviggi M.G.; Amaral Coutinho Y.; Ambler A.; Ambroz L.; Amelung C.; Amidei D.; Amor Dos Santos S.P.; Amoroso S.; Amrouche C.S.; Anastopoulos C.; Andari N.; Andeen T.; Anders J.K.; Andrean S.Y.; Andreazza A.; Angelidakis S.; Angerami A.; Anisenkov A.V.; Annovi A.; Antel C.; Anthony M.T.; Antipov E.; Antonelli M.; Antrim D.J.A.; Anulli F.; Aoki M.; Aparisi Pozo J.A.; Aparo M.A.; Aperio Bella L.; Aranzabal N.; Araujo Ferraz V.; Arcangeletti C.; Arce A.T.H.; Arena E.; Arguin J.-F.; Argyropoulos S.; Arling J.-H.; Armbruster A.J.; Armstrong A.; Arnaez O.; Arnold H.; Arrubarrena Tame Z.P.; Artoni G.; Asada H.; Asai K.; Asai S.; Asbah N.A.; Asimakopoulou E.M.; Asquith L.; Assahsah J.; Assamagan K.; Astalos R.; Atkin R.J.; Atkinson M.; Atlay N.B.; Atmani H.; Atmasiddha P.A.; Augsten K.; Auricchio S.; Austrup V.A.; Avner G.; Avolio G.; Ayoub M.K.; Azuelos G.; Babal D.; Bachacou H.; Bachas K.; Bachiu A.; Backman F.; Badea A.; Bagnaia P.; Bahrasemani H.; Bailey A.J.; Bailey V.R.; Baines J.T.; Bakalis C.; Baker O.K.; Bakker P.J.; Bakos E.; Bakshi Gupta D.; Balaji S.; Balasubramanian R.; Baldin E.M.; Balek P.; Ballabene E.; Balli F.; Balunas W.K.; Balz J.; Banas E.; Bandieramonte M.; Bandyopadhyay A.; Bansal S.; Barak L.; Barberio E.L.; Barberis D.; Barbero M.; Barbour G.; Barends K.N.; Barillari T.; Barisits M.-S.; Barkeloo J.; Barklow T.; Barnett B.M.; Barnett R.M.; Baroncelli A.; Barone G.; Barr A.J.; Barranco Navarro L.; Barreiro F.; Barreiro Guimaraes da Costa J.; Barron U.; Barsov S.; Bartels F.; Bartoldus R.; Bartolini G.; Barton A.E.; Bartos P.; Basalaev A.; Basan A.; Bashta I.; Bassalat A.; Basso M.J.; Basson C.R.; Bates R.L.; Batlamous S.; Batley J.R.; Batool B.; Battaglia M.; Bauce M.; Bauer F.; Bauer P.; Bawa H.S.; Bayirli A.; Beacham J.B.; Beau T.; Beauchemin P.H.; Becherer F.; Bechtle P.; Beck H.P.; Becker K.; Becot C.; Beddall A.J.; Bednyakov V.A.; Bee C.P.; Beermann T.A.; Begalli M.; Begel M.; Behera A.; Behr J.K.; Beirao Da Cruz E Silva C.; Beirer J.F.; Beisiegel F.; Belfkir M.; Bella G.; Bellagamba L.; Bellerive A.; Bellos P.; Beloborodov K.; Belotskiy K.; Belyaev N.L.; Benchekroun D.; Benhammou Y.; Benjamin D.P.; Benoit M.; Bensinger J.R.; Bentvelsen S.; Beresford L.; Beretta M.; Berge D.; Bergeaas Kuutmann E.; Berger N.; Bergmann B.; Bergsten L.J.; Beringer J.; Berlendis S.; Bernardi G.; Bernius C.; Bernlochner F.U.; Berry T.; Berta P.; Berthold A.; Bertram I.A.; Bessidskaia Bylund O.; Bethke S.; Betti A.; Bevan A.J.; Bhatta S.; Bhattacharya D.S.; Bhattarai P.; Bhopatkar V.S.; Bi R.; Bianchi R.M.; Biebel O.; Bielski R.; Biesuz N.V.; Biglietti M.; Billoud T.R.V.; Bindi M.; Bingul A.; Bini C.; Biondi S.; Biondini A.; Birch-sykes C.J.; Bird G.A.; Birman M.; Bisanz T.; Biswal J.P.; Biswas D.; Bitadze A.; Bittrich C.; Bjorke K.; Bloch I.; Blocker C.; Blue A.; Blumenschein U.; Blumenthal J.; Bobbink G.J.; Bobrovnikov V.S.; Boehler M.; Bogavac D.; Bogdanchikov A.G.; Bohm C.; Boisvert V.; Bokan P.; Bold T.; Bomben M.; Bona M.; Boonekamp M.; Booth C.D.; Borbely A.G.; Borecka-Bielska H.M.; Borgna L.S.; Borissov G.; Bortoletto D.; Boscherini D.; Bosman M.; Bossio Sola J.D.;
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