Next-to-leading QCD effect to the quark compositeness search at the LHC

TL;DR

This paper provides exact NLO QCD corrections to dijet production from quark contact interactions, revealing that previous scaled predictions overestimated effects and thus affected the limits on quark compositeness at the LHC.

Contribution

It presents the first exact NLO QCD calculations for quark contact interactions, improving the accuracy of theoretical predictions for LHC dijet analyses.

Findings

Scaled NLO predictions overestimate effects by over 30%.

Exact NLO corrections reduce the estimated quark compositeness scale limits.

Previous limits may need revision based on these more precise calculations.

Abstract

Recently, the CMS and ATLAS Collaborations at the CERN Large Hadron Collider (LHC) have set exclusion limits on the quark compositeness scale by comparing their data to the leading order and the scaled next-to-leading order (NLO) QCD calculations, respectively. In this Letter, we present the exact NLO QCD corrections to the dijet production induced by the quark contact interactions. We show that as compared to the exact calculation, the scaled NLO QCD prediction adopted by the ATLAS Collaboration has overestimated the new physics effect on some direct observables by more than 30% and renders a higher limit on the quark compositeness scale. The destructive contribution from the exact NLO correction will also lower the compositeness scale limit set by the CMS Collaboration.