LHC Probe of Quark Substructure at the Early Stages of Running

TL;DR

This paper investigates the potential to detect quark substructure at the LHC by analyzing high-energy dijet events, estimating the energy scale of compositeness, and setting limits based on interference effects.

Contribution

It introduces a novel observable for probing quark compositeness and estimates sensitivity to the energy scale at early LHC running stages.

Findings

Lower limits on the compositeness scale are about 10.5 TeV for constructive interference.

Sensitivity to interference sign affects the estimated energy scale.

Early LHC data can set significant bounds on quark substructure.

Abstract

We explore the opportunity to look for quark compositeness in the early stages of the LHC running by analyzing high-$E_T$ dijet production. The quark substructure that will manifest itself by affecting various kinematic distributions at the center-of-mass energy $E_{CM}$=10 TeV and in the integrated luminosity range from 0.5 to 10 fb$^{-1}$ is investigated. The estimation of the characteristic energy scale $\Lambda$, based on the novel, potentially powerful observable, is found to be sensitive to the sign of the interference between Standard Model and four-fermion contact interactions. We find the lower limits on $\Lambda$ at the LHC to be about 10.5(15.0) TeV for constructive interference and 8.5(11.5) TeV for destructive one at the integrated luminosity 0.5(10) fb$^{-1}$ and $E_{CM}=10$ TeV.