Measurement of the mass difference between top and anti-top quarks in pp collisions at √s=7 TeV using the ATLAS detector

G Aad; T Abajyan; B Abbott; J Abdallah; S Abdel Khalek; O Abdinov; R Aben; B Abi; M Abolins; OS AbouZeid; H Abramowicz; H Abreu; Y Abulaiti; BS Acharya; L Adamczyk; DL Adams; TN Addy; J Adelman; S Adomeit; T Adye; S Aefsky; T Agatonovic-Jovin; JA Aguilar-Saavedra; M Agustoni; SP Ahlen; A Ahmad; F Ahmadov; M Ahsan; G Aielli; TPA Åkesson; G Akimoto; AV Akimov; MA Alam; J Albert; S Albrand; MJ Alconada Verzini; M Aleksa; IN Aleksandrov; F Alessandria; C Alexa; G Alexander; G Alexandre; T Alexopoulos; M Alhroob; M Aliev; G Alimonti; L Alio; J Alison; BMM Allbrooke; LJ Allison; PP Allport; SE Allwood-Spiers; J Almond; A Aloisio; R Alon; A Alonso; F Alonso; A Altheimer; B Alvarez Gonzalez; MG Alviggi; K Amako; Y Amaral Coutinho; C Amelung; VV Ammosov; SP Amor Dos Santos; A Amorim; S Amoroso; N Amram; G Amundsen; C Anastopoulos; LS Ancu; N Andari; T Andeen; CF Anders; G Anders; KJ Anderson; A Andreazza; V Andrei; XS Anduaga; S Angelidakis; P Anger; A Angerami; F Anghinolfi; AV Anisenkov; N Anjos; A Annovi; A Antonaki; M Antonelli; A Antonov; J Antos; F Anulli; M Aoki; L Aperio Bella; R Apolle; G Arabidze; I Aracena; Y Arai; ATH Arce; S Arfaoui; JF Arguin

Journal article

Measurement of the mass difference between top and anti-top quarks in pp collisions at √s=7 TeV using the ATLAS detector

G Aad, T Abajyan, B Abbott, J Abdallah, S Abdel Khalek, O Abdinov, R Aben, B Abi, M Abolins, OS AbouZeid, H Abramowicz, H Abreu, Y Abulaiti, BS Acharya, L Adamczyk, DL Adams, TN Addy, J Adelman, S Adomeit, T Adye Show all

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics | Published : 2014

DOI: 10.1016/j.physletb.2013.12.010

Abstract

A measurement of the mass difference between top and anti-top quarks is presented. In a 4.7 fb−1 data sample of proton–proton collisions at s=7 TeV recorded with the ATLAS detector at the LHC, events consistent with tt¯ production and decay into a single charged lepton final state are reconstructed. For each event, the mass difference between the top and anti-top quark candidate is calculated. A two b-tag requirement is used in order to reduce the background contribution. A maximum likelihood fit to these per-event mass differences yields Δm≡mt−mt¯=0.67±0.61(stat)±0.41(syst) GeV, consistent with CPT invariance.