Asymmetric Left-Right Model and the Top Pair Forward-Backward Asymmetry

TL;DR

This paper proposes an asymmetric left-right model with new gauge bosons to explain the top-pair forward-backward asymmetry observed at the Tevatron, aligning with experimental data.

Contribution

It introduces a novel asymmetric left-right model featuring a $W'$ and $Z'$ boson to explain the asymmetry while fitting existing top-pair production data.

Findings

The model accounts for the observed asymmetry.

It remains consistent with total cross-section measurements.

The $W'$ and $Z'$ masses are approximately 175 GeV and 900 GeV, respectively.

Abstract

The forward-backward asymmetry measurement in top-pair production at the Tevatron is about $2\sigma$ from the Standard Model prediction. We propose an asymmetric left-right model, which includes a $W'$ boson with a right-handed coupling of down to top quark, and a $Z'$ boson with diagonal couplings to the up, top, and down quarks with $M_{W'}\approx175$ GeV and $M_{Z'}\approx 900$ GeV. The model accounts for the asymmetry while remaining consistent with the top-pair total cross-section and invariant mass distribution.