Measurement of top quark polarization in top-antitop events from proton-proton collisions at √s=7 TeV using the ATLAS detector

Aad, G. and Abajyan, T. and Abbott, B. and Abdallah, J. and Abdel, Khalek S. and Abdinov, O. and Aben, R. and Abi, B. and Abolins, M. and Abouzeid, O. S. and Abramowicz, H. and Abreu, H. and Abulaiti, Y. and Acharya, B. S. and Adamczyk, L. and Adams, D. L. and Addy, T. N. and Adelman, J. and Adomeit, S. and Adye, T. and Aefsky, S. and Agatonovic-Jovin, T. and Aguilar-Saavedra, J. A. and Agustoni, M. and Ahlen, S. P. and Ahmad, A. and Ahsan, M. and Aielli, G. and Åkesson, T. P. A. and Akimoto, G. and Krasznahorkay, Attila and Nagai, Yoshikazu and Pásztor, Gabriella and Tóth, József (2013) Measurement of top quark polarization in top-antitop events from proton-proton collisions at √s=7 TeV using the ATLAS detector. PHYSICAL REVIEW LETTERS, 111 (23). ISSN 0031-9007

Preview

Text 1307.6511v2.pdf Available under License Creative Commons Attribution. Download (1MB) | Preview

Abstract

This Letter presents measurements of the polarization of the top quark in top–antitop quark pair events, using 4.7 fb−1 of proton–proton collision data recorded with the ATLAS detector at the Large Hadron Collider at √ s = 7 TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of α`P, the product of the leptonic spin-analyzing power and the top quark polarization, are performed assuming that the polarization is introduced by either a CP conserving (CPC) or a CP violating (CPV) production process. The measurements obtained, α`PCPC = −0.035 ± 0.014(stat) ± 0.037(syst) and α`PCPV = 0.020 ± 0.016(stat)+0.013 −0.017(syst), are in good agreement with the Standard Model prediction of negligible top quark polarization.

Actions (login required)

Edit Item