Top pair Asymmetries at Hadron colliders with general $Z'$ couplings

TL;DR

This paper investigates the effects of a general $Z'$ gauge boson with various couplings on top pair asymmetries at hadron colliders, showing that certain models remain viable despite experimental constraints.

Contribution

It introduces a comprehensive analysis of $Z'$ couplings, including tensor interactions, and assesses their impact on top asymmetries considering flavor constraints.

Findings

$Z'$ models with specific couplings can still explain Tevatron FBA.

Charge asymmetry measurements at LHC do not fully exclude these models.

Flavor constraints from $B^0_q$ mixing limit the parameter space.

Abstract

Recently it has been shown that measurement of charge asymmetry of top pair production at LHC excludes any flavor violating $Z'$ vector gauge boson that could explain Tevatron forward-backward asymmetry (FBA). We consider the general form of a $Z'$ gauge boson including left-handed, right-handed vector and tensor couplings to examine FBA and charge asymmetry. To evaluate top pair asymmetries at Tevatron and LHC, we consider $B^0_q$ mixing constraints on flavor changing $Z'$ couplings and show that this model still explain forward-backward asymmetry at Tevatron and charge asymmetry can not exclude it in part of parameters space.