Heavy Color-Octet Particles at the LHC

TL;DR

This paper investigates heavy color-octet particles at the LHC, analyzing their decay channels, current experimental bounds, and future discovery prospects, including at a 100-TeV collider, with a focus on their properties and potential dark matter connections.

Contribution

It provides a comprehensive categorization of color-octet states, reviews current bounds, and studies discovery prospects and property determination at various collider energies.

Findings

Current LHC bounds on color-octet states

Projected discovery reach at 8-TeV and 14-TeV LHC runs

Production rates at a future 100-TeV collider

Abstract

Many new-physics models, especially those with a color-triplet top-quark partner, contain a heavy color-octet state. The "naturalness" argument for a light Higgs boson requires that the color-octet state be not much heavier than a TeV, and thus it can be pair-produced with large cross sections at high-energy hadron colliders. It may decay preferentially to a top quark plus a top-partner, which subsequently decays to a top quark plus a color-singlet state. This singlet can serve as a WIMP dark-matter candidate. Such decay chains lead to a spectacular signal of four top quarks plus missing energy. We pursue a general categorization of the color-octet states and their decay products according to their spin and gauge quantum numbers. We review the current bounds on the new states at the LHC and study the expected discovery reach at the 8-TeV and 14-TeV runs. We also present the production rates at a future 100-TeV hadron collider, where the cross sections will be many orders of magnitude greater than at the 14-TeV LHC. Furthermore, we explore the extent to which one can determine the color octet's mass, spin, and chiral couplings. Finally, we propose a test to determine whether the fermionic color octet is a Majorana particle.