Multiple Hard Parton Interactions at HERA

Abstract

At HERA, the large flux of almost real photons accompanying the electron beam leads to the copious photoproduction of jets. Regions of small momentum fractions $x$ of the incoming particles are explored, where the density of partons is high. As a result, the probability for more than one hard partonic scattering occurring in a single $\gamma p$ collision could become significant. It is well known that this effect modifies the contribution of jets (minijets) to the total cross section. We discuss the latest HERA data on the total $\gamma p$ cross section in this context. The possible effects of multiple hard interactions on event shapes and jet cross sections at HERA have been studied using Monte Carlo programs. We review some of the available results, which in general indicate that the effects of multiple interactions should be significant and may already be manifest in the existing HERA data.

12 pages LATEX with 4 figures in a single uuuencoded file

References in corpus (3)

• Total cross sections
• Dijet Cross Sections in Photoproduction at HERA
• Parton distributions of real and virtual photons

Cited by in corpus (6)

• QCD coherence and the soft limit of the energy spectrum
• Three- and four-jet final states in photoproduction at HERA
• Hard underlying event correction to inclusive jet cross sections
• A search for an excited muon decaying to a muon and two jets in $pp$ collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector
• Parton distributions of real and virtual photons
• Investigating Heavy-flavor vs Light-flavor Puzzle with Event Topology and Multiplicity in Proton+Proton Collisions at $\sqrt{s}$ = 13 TeV using PYTHIA8