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Title: Energy Flow and Leading Neutron Production at HERA

Abstract

The azimuthal asymmetry of hadrons in the semi-inclusive process e+p {yields} e+h+X is studied in deep inelastic scattering at HERA. A measurement of the dijet cross section with a leading neutron is also reported, the P{sub T}{sup 2} distribution of the leading neutron is investigated.

Authors:
 [1]
  1. DESY, Hamburg (Germany)
Publication Date:
OSTI Identifier:
20800077
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: 10.1063/1.2197415; (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; ASYMMETRY; CROSS SECTIONS; DEEP INELASTIC SCATTERING; DISTRIBUTION; ELECTRON-PROTON INTERACTIONS; HERA STORAGE RING; JET MODEL; NEUTRONS; TRANSVERSE MOMENTUM

Citation Formats

Yan Wenbiao. Energy Flow and Leading Neutron Production at HERA. United States: N. p., 2006. Web. doi:10.1063/1.2197415.
Yan Wenbiao. Energy Flow and Leading Neutron Production at HERA. United States. doi:10.1063/1.2197415.
Yan Wenbiao. Tue . "Energy Flow and Leading Neutron Production at HERA". United States. doi:10.1063/1.2197415.
@article{osti_20800077,
title = {Energy Flow and Leading Neutron Production at HERA},
author = {Yan Wenbiao},
abstractNote = {The azimuthal asymmetry of hadrons in the semi-inclusive process e+p {yields} e+h+X is studied in deep inelastic scattering at HERA. A measurement of the dijet cross section with a leading neutron is also reported, the P{sub T}{sup 2} distribution of the leading neutron is investigated.},
doi = {10.1063/1.2197415},
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}
}
  • Events with a high energy neutron produced at small angles with respect to the proton beam direction have been observed by the H1 experiment at HERA. The observed energy and |t| distributions of final-state neutrons with energy E{sub n}{>=}400 GeV are in good agreement with the predictions of Monte Carlo models based on pion exchange, and with those based on string fragmentation. In the kinematic range 5{<=}Q{sup 2}{<=}100 GeV{sup 2} and 0.05{<=}y{<=}0.7, the fraction of e-p collisions which contain a neutron with E{sub n}{>=}400 GeV and |t|<0.5 GeV{sup 2} is (7.8{sub -2.0}{sup +3.0})%. The fraction of DIS events which containmore » a neutron with E{sub n}{>=}100 GeV is independent of Q{sup 2} and x{sub BJ}, and is consistent with having the same multiplicity distribution as does the fully inclusive DIS sample.« less
  • No abstract prepared.
  • The production of forward jets of transverse momentum p{sub T}(j){approx}Q and large momentum fraction x{sub jet}{gt}x probes the onset of Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics at DESY HERA. A full O({alpha}{sup 2}{sub s}) calculation of the inclusive forward jet cross section is presented and compared to the expected BFKL cross section. The kinematical region populated by these events and the scale dependence of the fixed order perturbative QCD cross sections are discussed. {copyright} {ital 1997} {ital The American Physical Society}
  • We calculate the cross section of inclusive direct J/{psi} hadroproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics, including the full relativistic corrections due to the intermediate {sup 1}S{sub 0}{sup [8]}, {sup 3}S{sub 1}{sup [8]}, and {sup 3}P{sub J}{sup [8]} color-octet states. We perform a combined fit of the color-octet long-distance matrix elements to the transverse-momentum (p{sub T}) distributions measured by CDF at the Fermilab Tevatron and H1 at DESY HERA and demonstrate that they also successfully describe the p{sub T} distributions from PHENIX at BNL RHIC and CMS at the CERN LHC as well as themore » photon-proton c.m. energy and (with worse agreement) the inelasticity distributions from H1. This provides a first rigorous test of nonrelativistic QCD factorization at next-to-leading order. In all experiments, the color-octet processes are shown to be indispensable.« less
  • Measurements are reported of the production of dijet events with a leading neutron in ep interactions at HERA. Differential cross sections for photoproduction and DIS are presented. LO QCD simulation programs and NLO perturbative QCD calculations are compared with the measurements. Models in which the real or virtual photon interacts with a parton of an exchanged pion are found to be in good agreement with the measured cross sections. The fraction of leading neutron dijet events with respect to all dijet events is also determined.