Discerning New Physics in Top-Antitop Production using Top Spin Observables at Hadron Colliders

Abstract

Copious production of top-antitop quark pairs at hadron colliders has enabled various probes into the properties and interactions of top quarks. Among the various presently measured observables, the forward-backward asymmetry (FBA) in t tbar production measured at the Tevatron significantly deviates from the standard model predictions, and many models of new physics have been invented to explain the puzzle. We consider the consistency of the simplified single-resonance models containing a color octet axial-vector ("axigluon"), color triplet or sextet weak singlet scalars, weak isodoublet scalar, flavor-changing neutral Z', or charged W' vector boson with existing t tbar production measurements. Among the considered models only an axigluon can reproduce all Tevatron observables, without being in severe tension with the recent LHC results on t tbar production cross section, charge asymmetry and top-spin correlations. The LHC charge asymmetry measurements exclude the W' and Z' explanations of the Tevatron FBA anomaly. On the other hand, all scalar models predict notable deviations in several top spin observables, and the recent top spin correlation measurement using the "helicity" spin quantization axis by ATLAS already provides a significant constraint on possible explanations of the Tevatron FBA anomaly. Future precise measurements of top spin correlations and especially top polarization could differentiate between scalar t(u)-channel models, while they are less sensitive to pure axigluon contributions.

22 pages, 8 figures, published version

References in corpus (16)

• Parton distributions for the LHC
• Next-to-next-to-leading soft-gluon corrections for the top quark cross section and transverse momentum distribution
• Top Quarks, Axigluons and Charge Asymmetries at Hadron Colliders
• Measurement of the charge asymmetry in top quark pair production in pp collisions at sqrt(s) = 7 TeV using the ATLAS detector
• Observation of Single Top Quark Production and Measurement of |Vtb| with CDF
• Spin Correlation Effects in Top Quark Pair Production at the LHC
• Constraining heavy colored resonances from top-antitop quark events
• Probing the Tevatron t tbar asymmetry at LHC
• Forward-backward asymmetry in top quark production from light colored scalars in SO(10) model
• No like-sign tops at Tevatron: Constraints on extended models and implications for the t tbar asymmetry
• The top quark rapidity distribution and forward-backward asymmetry
• On measurement of top polarization as a probe of $t\bar{t}$ production mechanisms at the LHC
• Top quark forward-backward asymmetry at Tevatron and its implications at the LHC
• Measurement of spin correlation in ttbar production using dilepton final states
• Flipping t tbar asymmetries at the Tevatron and the LHC
• Gluon excitations in t tbar production at hadron colliders

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