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Home > Research > Publications & Outputs > Evidence for spin correlation in ttbar production

## Evidence for spin correlation in ttbar production

Research output: Contribution to journalJournal article

Published

Article number 032004 19/01/2012 Physical Review Letters 3 108 7 English

### Abstract

We present a measurement of the ratio of events with correlated t and tbar spins to the total number of ttbar events. This ratio f is evaluated using a matrix-element-based approach in events with a single lepton (electron or muon) and at least four jets. We analyze ppbar collisions data corresponding to an integrated luminosity of 5.3 fb^-1 collected with the D0 detector at the Fermilab Tevatron collider operating at a center of mass energy $\sqrt{s}=1.96$ TeV. Combining this result with a recent measurement of f in dilepton final states, we find f in agreement with the standard model. In addition, the combination provides evidence for the presence of spin correlation in ttbar events with a significance of more than three standard deviations.

### Bibliographic note

© 2012 American Physical Society 7 pages, 2 figures