T-Quarks at the Large Hadron Collider: 2010-12

TL;DR

This paper assesses the Large Hadron Collider's ability to detect heavy T-odd quarks predicted by the Littlest Higgs model with T-parity, providing bounds and future prospects based on current and projected data.

Contribution

It estimates current experimental bounds and future discovery potential for T-odd quarks at the LHC, incorporating analysis of existing CMS data and strategies for near-degenerate scenarios.

Findings

T-quark masses below ~450 GeV are excluded for LTP mass ~100 GeV.

Projected bounds could reach ~650 GeV with 1 fb-1 of data.

Using initial-state radiation jets can help constrain nearly-degenerate T-quark and LTP regions.

Abstract

We study the potential of the current Large Hadron Collider (LHC) 7 TeV run to search for heavy, colored vector-like fermions, which are assumed to carry a conserved Z2 quantum number forcing them to be pair-produced. Each fermion is assumed to decay directly into a Standard Model quark and an invisible stable particle. T-odd quarks (T-quarks) and the lightest T-odd particle (LTP) of the Littlest Higgs model with T-parity provide an example of this setup. We estimate the bounds based on the published CMS search for events with jets and missing transverse energy in the 35 pb-1 data set collected in the 2010 run. We find that T-quark masses below about 450 GeV are ruled out for the LTP mass about 100 GeV. This bound is somewhat stronger than the published Tevatron constraint. We also estimate the reach with higher integrated luminosities expected in the 2011-12 run. If no deviation from the SM is observed, we expect that a bound on the T-quark mass of about 650 GeV, for the LTP mass of 300 GeV and below, can be achieved with 1 fb-1 of data. We comment on the possibility of using initial-state radiation jets to constrain the region with nearly-degenerate T-quark and LTP.