Transverse top quark polarization and the tt̄ forward-backward asymmetry

Matthew Baumgart, Brock Tweedie

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The forward-backward asymmetry in top pair production at the Tevatron has long been in tension with the Standard Model prediction. One of the only viable new physics scenarios capable of explaining this anomaly is an s-channel axigluon-like resonance, with the quantum numbers of the gluon but with significant axial couplings to quarks. While such a resonance can lead to a clear bump or excess in the tt̄ or dijet mass spectra, it may also simply be too broad to cleanly observe. Here, we point out that broad tt̄ resonances generally lead to net top and antitop polarizations transverse to the production plane. This polarization is consistent with all discrete spacetime symmetries, and, analogous to the forward-backward asymmetry itself, is absent in QCD at leading order. Within the parameter space consistent with the asymmetry measurements, the induced polarization can be sizable, and might be observable at the Tevatron or the LHC.

Original languageEnglish (US)
Article number72
JournalJournal of High Energy Physics
Issue number8
StatePublished - 2013
Externally publishedYes


  • Beyond Standard Model
  • Heavy Quark Physics
  • QCD

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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