Physics Letters B
The consistency of the spin correlation strength in top quark pair production with the standard model (SM) prediction is tested in the muon+jets final state. The events are selected from pp collisions, collected by the CMS detector, at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The data are compared with the expectation for the spin correlation predicted by the SM and with the expectation of no correlation. Using a template fit method, the fraction of events that show SM spin correlations is measured to be 0.72±0.08(stat)+0.15-0.13(syst), representing the most precise measurement of this quantity in the muon+jets final state to date.
Baarmand, M M.; Bhopatkar, Vallary; Hohlmann, Marcus; Kalakhety, H; Noonan, D; Roy, Tuhin S.; Yumiceva, Francisco X.; and CMS Collaboration, "Measurement Of Spin Correlations In tt Production Using The Matrix Element Method In The Muon+jets Final State In pp Collisions At √s=8 TeV" (2016). Aerospace, Physics, and Space Science Faculty Publications. 131.