Composite Octet Searches with Jet Substructure

TL;DR

This paper explores the use of jet substructure techniques at the LHC to detect composite octet mesons predicted by models with strongly interacting sectors, analyzing different decay modes and mass hierarchies.

Contribution

It develops and compares simple jet mass and advanced jet substructure analyses for discovering composite octets in dijet signatures at the LHC.

Findings

Jet substructure enhances sensitivity for certain mass hierarchies.

Optimal analysis method depends on the pseudoscalar-to-vector meson mass ratio.

Different strategies are recommended based on the mass hierarchy.

Abstract

Many new physics models with strongly interacting sectors predict a mass hierarchy between the lightest vector meson and the lightest pseudoscalar mesons. We examine the power of jet substructure tools to extend the 7 TeV LHC sensitivity to these new states for the case of QCD octet mesons, considering both two gluon and two b-jet decay modes for the pseudoscalar mesons. We develop both a simple dijet search using only the jet mass and a more sophisticated jet substructure analysis, both of which can discover the composite octets in a dijet-like signature. The reach depends on the mass hierarchy between the vector and pseudoscalar mesons. We find that for the pseudoscalar-to-vector meson mass ratio below approximately 0.2 the simple jet mass analysis provides the best discovery limit; for a ratio between 0.2 and the QCD-like value of 0.3, the sophisticated jet substructure analysis has the best discovery potential; for a ratio above approximately 0.3, the standard four-jet analysis is more suitable.