LHC Charge Asymmetry as Constraint on Models for the Tevatron Top Anomaly

TL;DR

This paper investigates how LHC charge asymmetry measurements can constrain models explaining the Tevatron top quark forward-backward asymmetry anomaly, focusing on a $W'$ model and its implications for new physics detection.

Contribution

It demonstrates that charge asymmetry at the LHC can effectively test and potentially exclude $W'$ models proposed for the Tevatron top anomaly, even with limited 2010 data.

Findings

Charge asymmetry measurements can strongly constrain $W'$ models.

LHC data can discover or exclude models explaining the Tevatron anomaly.

Charge asymmetry is a powerful tool for probing new physics in top quark production.

Abstract

The forward-backward asymmetry $A_{FB}^{t\bar t}$ in top quark production at the Tevatron has been observed to be anomalously large by both CDF and D0. It has been suggested that a model with a $W'$ coupling to $td$ and $ub$ might explain this anomaly, and other anomalies in $B$ mesons. Single-top-quark production in this model is large, and arguably in conflict with Tevatron measurements. However the model might still be viable if $A_{FB}^{t\bar t}$ is somewhat smaller than its current measured central value. We show that even with smaller couplings, the model can be discovered (or strongly excluded) at the LHC using the 2010 data sets. We find that a suitable charge-asymmetry measurement is a powerful tool that can be used to constrain this and other sources of anomalous single-top production, and perhaps other new high-energy charge-asymmetric processes.