Charge asymmetry of top quarks

TL;DR

This paper explores how heavy colored resonances could cause charge asymmetry in top quark production at the LHC and Tevatron, analyzing constraints and potential signatures of such new physics models.

Contribution

It introduces a toy model with flavor-dependent couplings to study charge asymmetry effects and proposes a new central asymmetry observable for LHC detection.

Findings

Constraints on resonance couplings from Tevatron asymmetry measurements

Potential LHC signatures of charge asymmetry in specific kinematic regions

Statistical significance estimates for asymmetry detection at the LHC

Abstract

The LHC is a promising machine to discover new physics in the top sector. There are several models that predict the existence of heavy colored resonances decaying to top quarks in the TeV energy range. The production of such resonances might generate a sizable charge asymmetry of top versus antitop quarks. At the Tevatron, a 2 sigma discrepancy with the SM prediction for the forward--backward asymmetry has been found, boosting a renewed interest for this kind of models. We consider a toy model with general flavour dependent couplings of the resonance to quarks, of both vector and axial-vector kind and investigate the possible constraints on the coupling space from the measurement of the asymmetry and the invariant mass distribution at the Tevatron. Then, we define a central asymmetry in a specific kinematic region and investigate its signature at the LHC as well as its statistical significance, for exclusive processes.