Measurement of spin correlation between top and antitop quarks produced in pp¯ collisions at √s = 1.96 TeV

UNSPECIFIED (2016) Measurement of spin correlation between top and antitop quarks produced in pp¯ collisions at √s = 1.96 TeV. Physics Letters B, 757. pp. 199-206. ISSN 0370-2693

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Abstract

Abstract We present a measurement of the correlation between the spins of t and t ¯ quarks produced in proton–antiproton collisions at the Tevatron Collider at a center-of-mass energy of 1.96 TeV. We apply a matrix element technique to dilepton and single-lepton+jets final states in data accumulated with the D0 detector that correspond to an integrated luminosity of 9.7   fb − 1 . The measured value of the correlation coefficient in the off-diagonal basis, O off = 0.89 ± 0.22 ( stat + syst ) , is in agreement with the standard model prediction, and represents evidence for a top–antitop quark spin correlation difference from zero at a level of 4.2 standard deviations.