Three-Jet Production in Deep-Inelastic Scattering at HERA

TL;DR

This paper reports the first measurement of three-jet production in deep-inelastic scattering at HERA, demonstrating that perturbative QCD accurately predicts cross sections and jet angular distributions across a wide kinematic range.

Contribution

It provides the first experimental study of three-jet events in deep-inelastic scattering and confirms NLO QCD predictions for cross sections and angular distributions.

Findings

Three-jet cross section matches NLO QCD predictions.

The ratio R_(3/2) is well described by QCD calculations.

Jet angular distributions deviate from uniform phase space, aligning with QCD models.

Abstract

Three-jet production is studied for the first time in deep-inelastic positron-proton scattering. The measurement carried out with the H1 detector at HERA covers a large range of four-momentum transfer squared 5 < Q^2 < 5000 GeV^2 and invariant three-jet masses 25 < M_(3jet) < 140 GeV. Jets are defined by the inclusive k_T algorithm in the Breit frame. The size of the three-jet cross section and the ratio of the three-jet to the dijet cross section R_(3/2) are described over the whole phase space by the predictions of perturbative QCD in next-to-leading order. The shapes of angular jet distributions deviate significantly from a uniform population of the available phase space but are well described by the QCD calculation.