Low Q^2 Jet Production at HERA and Virtual Photon Structure

TL;DR

This paper investigates jet production at HERA to understand the transition from photoproduction to deep-inelastic scattering, revealing that QCD models with a virtual photon structure evolving with Q2 best describe the data.

Contribution

It provides the first detailed measurements of jet cross-sections across a range of Q2, supporting models of a virtual photon with a Q2-dependent partonic structure.

Findings

Data agree with QCD calculations including a virtual photon structure.

Jet cross-sections vary with Q2, indicating photon structure evolution.

Results support the partonic description of the virtual photon.

Abstract

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.