Multijet production in neutral current deep inelastic scattering at HERA and determination of alpha_s

TL;DR

This study measures multijet production in neutral current deep inelastic scattering at HERA, compares results with QCD predictions, and determines the strong coupling constant alpha_s with high precision.

Contribution

It provides detailed measurements of multijet cross sections and extracts alpha_s(M_Z) using NLO QCD calculations, enhancing understanding of QCD at high energies.

Findings

NLO QCD describes the data well.

Measured alpha_s(M_Z) = 0.1179 ± 0.0013 (stat.) +0.0028/-0.0046 (exp.) +0.0064/-0.0046 (th.)

Differential cross sections agree with theoretical predictions.

Abstract

Multijet production rates in neutral current deep inelastic scattering have been measured in the range of exchanged boson virtualities 10 < Q2 < 5000 GeV2. The data were taken at the ep collider HERA with centre-of-mass energy sqrt(s) = 318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82.2 pb-1. Jets were identified in the Breit frame using the k_T cluster algorithm in the longitudinally invariant inclusive mode. Measurements of differential dijet and trijet cross sections are presented as functions of jet transverse energy E_{T,B}{jet}, pseudorapidity eta_{LAB}{jet} and Q2 with E_{T,B}{jet} > 5 GeV and -1 < eta_{LAB}{jet} < 2.5. Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant alpha_s(M_Z), determined from the ratio of the trijet to dijet cross sections, is alpha_s(M_Z) = 0.1179 pm 0.0013(stat.) {+0.0028}_{-0.0046}(exp.) {+0.0064}_{-0.0046}(th.)