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Title: Jets in Photoproduction and at Low Q2 at HERA

Abstract

Recent H1 and ZEUS measurements of two and three jet cross sections in electron-proton interactions in the photoproduction region or at low photon virtuality, Q 2, are presented and compared to NLO QCD calculations. Phase space regions where data are not well reproduced by the NLO theory are pointed out. A recent ZEUS measurement of color dynamics sensitive to the underlying gauge group in QCD is presented.

Authors:
 [1]
  1. Department of Physics, Oxford University, Oxford (United Kingdom)
Publication Date:
OSTI Identifier:
20800078
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 828; Journal Issue: 1; Conference: 35. internationals symposium on multiparticle dynamics; Workshop on particle correlations and femtoscopy, Kromeriz (Czech Republic), 9-17 Aug 2005; Other Information: DOI: 10.1063/1.2197416; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CROSS SECTIONS; DEEP INELASTIC SCATTERING; ELECTRON-PROTON INTERACTIONS; FOUR MOMENTUM TRANSFER; HADRONS; HERA STORAGE RING; JET MODEL; MULTIPARTICLE SPECTROMETERS; PARTICLE IDENTIFICATION; PHASE SPACE; PHOTONS; PHOTOPRODUCTION; QUANTUM CHROMODYNAMICS

Citation Formats

Sedlak, Kamil. Jets in Photoproduction and at Low Q2 at HERA. United States: N. p., 2006. Web. doi:10.1063/1.2197416.
Sedlak, Kamil. Jets in Photoproduction and at Low Q2 at HERA. United States. doi:10.1063/1.2197416.
Sedlak, Kamil. Tue . "Jets in Photoproduction and at Low Q2 at HERA". United States. doi:10.1063/1.2197416.
@article{osti_20800078,
title = {Jets in Photoproduction and at Low Q2 at HERA},
author = {Sedlak, Kamil},
abstractNote = {Recent H1 and ZEUS measurements of two and three jet cross sections in electron-proton interactions in the photoproduction region or at low photon virtuality, Q 2, are presented and compared to NLO QCD calculations. Phase space regions where data are not well reproduced by the NLO theory are pointed out. A recent ZEUS measurement of color dynamics sensitive to the underlying gauge group in QCD is presented.},
doi = {10.1063/1.2197416},
journal = {AIP Conference Proceedings},
number = 1,
volume = 828,
place = {United States},
year = {Tue Apr 11 00:00:00 EDT 2006},
month = {Tue Apr 11 00:00:00 EDT 2006}
}
  • The proton structure function F2 is measured using inelastic QED Compton events. The data were collected by H1 experiment at the HERA in 1997 and correspond to a luminosity of 9.25 pb-1. QED Compton events allow to access very low Q2 region, down to 0.5 GeV2 and Bjorken x up to {approx} 0.06, a region that has not been covered by previous inclusive measurements at HERA. The results are in agreement with measurements from fixed targed lepton-nucleon scattering experiments.
  • Inclusive ep scattering measurements at low virtualities of the exchanged boson, Q2, allow precision tests of perturbative QCD at high gluon densities, as well as studies of the transition from the perturbative to non-perturbative QCD domain. Measurements in the transition region require special experimental approaches due to the limited detector acceptance. The current status and results of low Q2 measurements at HERA are summarised.
  • The focus of this report are the recent measurements of the cross section and proton structure function F2 in ep deep inelastic scattering (DIS) at low virtuality of the exchanged boson, Q2, with the H1 detector at the HERA accelerator in Hamburg. The region of low Q2 and low Bjorken x allows precision tests of perturbative QCD at high gluon densities to be performed and also the transition from the perturbative to non-perturbative QCD domains to be explored. The recent H1 measurements of charm and beauty cross sections and structure functions, F{sub 2}{sup cc-bar} ans F{sub 2}{sup bb-bar}, for photonmore » virtuality 12 < Q2 < 60 GeV2 will also be discussed.« less
  • A new next-to-leading order Monte Carlo program for the calculation of jet cross sections in photoproduction is described. The contributions from both resolved and direct components are included to O({alpha}{alpha}{sub s}{sup 2}). Properties of the predictions for various inclusive jet and dijet observables are discussed and comparisons with DESY HERA data are presented. {copyright} {ital 1997} {ital The American Physical Society}
  • The photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 39 pb{sup -1}. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value ET CUT. The data show a clear excess over the predictions of standard photoproduction models. This is interpreted as evidence for a strongly interacting exchange of a color-singlet object. Monte Carlo models which include suchmore » a color-singlet exchange are able to describe the data.« less