Light axigluon explanation of the Tevatron ttbar asymmetry and multijet signals at the LHC

TL;DR

This paper evaluates a light axigluon model as an explanation for the Tevatron ttbar asymmetry, considering constraints from LHC data, and explores potential multijet signatures for future detection.

Contribution

It updates the light axigluon model's viability in explaining the asymmetry and proposes four decay scenarios for multijet signals at the LHC.

Findings

A 100-400 GeV axigluon fits the asymmetry data well.

Dijet resonance searches exclude axigluons with large dijet branching fractions.

Multijet decay channels remain a viable detection avenue.

Abstract

The ttbar asymmetry measured at the Tevatron continues to disagree with Standard Model predictions at the 3 sigma level. We update the status of the phenomenological light axigluon model in explaining the asymmetry data, taking into account constraints from the charge asymmetry at the LHC and the ttbar cross section at both Tevatron and LHC. We find that an axigluon with a mass between 100 and 400 GeV provides an excellent fit to the data. Recent searches by ATLAS and CMS for pair production of heavy resonances which decay to dijets rule out axigluons with large branching fractions to dijets. However axigluons which predominantly decay to multijets via intermediate resonances are still a possibility. We outline four distinct scenarios which cover the most important decay topologies and discuss how one might exclude or discover axigluons as multijet resonances at the LHC. MadGraph implementations for each of the scenarios are provided.