Top quark pair production and asymmetry at the Tevatron and LHC in left-right models

Abstract

In light of the recent measurements of the top quark forward-backward asymmetry at the Fermilab Tevatron experiment, which in some regions of the parameter space shows a discrepancy of $3\ensuremath{\sigma}$ compared to the standard model prediction, we analyze top quark pair production and asymmetry in the context of left-right models both at the Tevatron and Large Hadron Collider (LHC). We use the minimal manifest left-right model and an asymmetric left-right model where gauge couplings and flavor mixing in the right-handed sector are allowed to differ from those in the left-handed sector. We explore the consequences of including effects from ${W}_{R}$ and ${Z}_{R}$ gauge bosons, consistent with phenomenological constraints from meson mixing and new bounds from ATLAS and CMS, for the $t\overline{t}$ cross section, invariant mass distribution and forward-backward asymmetry at the Tevatron, and predict their values at the LHC. We show that, choosing parameter benchmarks for the model while preserving agreement with collider, electroweak precision, and flavor-violation data, the generic left-right model cannot account for the large deviations of the observed asymmetry at the Tevatron and also that it predicts very small charge asymmetries at the LHC.