Jet Production in ep Collisions at Low Q^2 and Determination of alpha_s

TL;DR

This paper measures jet production in low Q^2 deep-inelastic ep scattering at HERA, compares results with QCD predictions, and extracts the strong coupling constant alpha_s with high precision.

Contribution

It provides detailed measurements of jet cross sections at low Q^2 and uses these to determine alpha_s, advancing understanding of QCD in this regime.

Findings

Jet cross sections agree with NLO QCD predictions after corrections.

The strong coupling alpha_s is extracted with competitive precision.

Results support the validity of perturbative QCD at low Q^2.

Abstract

The production of jets is studied in deep-inelastic e+p scattering at low negative four momentum transfer squared 5<Q^2<100 GeV^2 and at inelasticity 0.2<y<0.7 using data recorded by the H1 detector at HERA in the years 1999 and 2000, corresponding to an integrated luminosity of 43.5 pb^-1. Inclusive jet, 2-jet and 3-jet cross sections as well as the ratio of 3-jet to 2-jet cross sections are measured as a function of Q^2 and jet transverse momentum. The 2-jet cross section is also measured as a function of the proton momentum fraction xi. The measurements are well described by perturbative quantum chromodynamics at next-to-leading order corrected for hadronisation effects and are subsequently used to extract the strong coupling alpha_s.