New Physics from the Top at the LHC

TL;DR

This paper explores new physics involving the top quark at the LHC, focusing on detecting a heavy, stable particle that couples to the top and could be dark matter, proposing optimized search strategies and analyzing potential signals.

Contribution

It systematically categorizes interactions of a new top-coupled particle, proposes optimized LHC search strategies, and demonstrates the detectability and distinguishability of spin-zero top partners.

Findings

A spin-zero top partner can be observed at 5-sigma for 675 GeV mass at 14 TeV with 100 fb^-1.

Spin-zero particles can be distinguished from other spins at 5-sigma with 10 fb^-1.

Optimized search strategies improve detection prospects for new top-related physics.

Abstract

The top quark may hold the key to new physics associated with the electroweak symmetry-breaking sector, given its large mass and enhanced coupling to the Higgs sector. We systematically categorize generic interactions of a new particle that couples to the top quark and a neutral particle, which is assumed to be heavy and stable, thus serving as a candidate for cold dark matter. The experimental signatures for new physics involving top quarks and its partners at the Large Hadron Collider (LHC) may be distinctive, yet challenging to disentangle. We optimize the search strategy at the LHC for the decay of the new particle to a top quark plus missing energy and propose the study of its properties, such as its spin and couplings. We find that, at 14 TeV with an integrated luminosity of 100 fb^-1, a spin-zero top partner can be observed at the 5-sigma level for a mass of 675 GeV. A spin-zero particle can be differentiated from spin-1/2 and spin-1 particles at the 5-sigma level with a luminosity of 10 fb^-1.