Determination of the strong coupling constant using subjet multiplicities in Neutral Current Deep Inelastic Scattering

TL;DR

This paper measures the strong coupling constant in deep inelastic scattering by analyzing jet substructure, specifically subjet multiplicities, and compares experimental data with next-to-leading order QCD calculations.

Contribution

It provides a novel extraction of alpha_s(M_Z) using subjet multiplicities in neutral current deep inelastic scattering at HERA.

Findings

Good agreement between NLO QCD and data for E_{T,jet}> 25 GeV

Extracted alpha_s(M_Z)=0.1185 with quantified uncertainties

Demonstrated the effectiveness of subjet analysis for alpha_s determination

Abstract

The internal structure of the jets produced in neutral current interactions for Q^2>125 GeV^2 has been studied using the subjet multiplicity with the ZEUS detector at HERA. Jets are identified in the laboratory frame by applying the longitudinally invariant k_T-cluster algorithm. Next-to-leading order QCD calculations have been obtained and compared to the data; a good agreement has been observed in the region where hadron-to-parton corrections are small, E_{T,jet}> 25 GeV. In this region, the strong coupling constant is extracted and the resulting value is alpha_s (M_Z)=0.1185 +/- 0.0016 (stat.) ^{+0.0067}_{-0.0048} (syst.) ^{+0.0089}_{-0.0071} (th.).