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Title: Recent measurement of {delta}G/G at COMPASS

Abstract

We present a preliminary measurement of the gluon polarization {delta}G/G in the nucleon, based on the spin asymmetry of quasi-real photoproduction events for which a pair of large transverse momentum hadrons is produced. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarized muon beam scattered on a large polarized 6LiD target. The preliminary helicity asymmetry for the selected events is A{sub paralle}Ll /D = 0.002 {+-} 0.019(stat.) {+-} 0.003(exp.syst.). From this value, a leading order analysis based on the model of PYTHIA leads to the gluon polarization in the nucleon {delta}G/G(xg = 0.095, {mu}2 = 3 GeV2) = 0.024 {+-} 0.089(stat.) {+-} 0.057(syst.). This value is consistent with parameterizations obtained from QCD fits to the g1 data, with a first moment {delta}G {identical_to} {integral}{sub 0}{sup 1} {delta}G(x)dx {approx_equal} 0.5, at the same scale.

Authors:
Publication Date:
OSTI Identifier:
20726400
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 792; Journal Issue: 1; Conference: DIS 2005: 13. international workshop on deep inelastic scattering, Madison, WI (United States), 27 Apr - 1 May 2005; Other Information: DOI: 10.1063/1.2122209; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; CERN; GEV RANGE; GLUONS; HELICITY; LEPTON-NUCLEON INTERACTIONS; MULTIPARTICLE SPECTROMETERS; MUON BEAMS; NUCLEONS; PARTICLE IDENTIFICATION; PHOTOPRODUCTION; POLARIZATION; QUANTUM CHROMODYNAMICS; SPIN; TRANSVERSE MOMENTUM

Citation Formats

Bernet, C. Recent measurement of {delta}G/G at COMPASS. United States: N. p., 2005. Web. doi:10.1063/1.2122209.
Bernet, C. Recent measurement of {delta}G/G at COMPASS. United States. https://doi.org/10.1063/1.2122209
Bernet, C. 2005. "Recent measurement of {delta}G/G at COMPASS". United States. https://doi.org/10.1063/1.2122209.
@article{osti_20726400,
title = {Recent measurement of {delta}G/G at COMPASS},
author = {Bernet, C},
abstractNote = {We present a preliminary measurement of the gluon polarization {delta}G/G in the nucleon, based on the spin asymmetry of quasi-real photoproduction events for which a pair of large transverse momentum hadrons is produced. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarized muon beam scattered on a large polarized 6LiD target. The preliminary helicity asymmetry for the selected events is A{sub paralle}Ll /D = 0.002 {+-} 0.019(stat.) {+-} 0.003(exp.syst.). From this value, a leading order analysis based on the model of PYTHIA leads to the gluon polarization in the nucleon {delta}G/G(xg = 0.095, {mu}2 = 3 GeV2) = 0.024 {+-} 0.089(stat.) {+-} 0.057(syst.). This value is consistent with parameterizations obtained from QCD fits to the g1 data, with a first moment {delta}G {identical_to} {integral}{sub 0}{sup 1} {delta}G(x)dx {approx_equal} 0.5, at the same scale.},
doi = {10.1063/1.2122209},
url = {https://www.osti.gov/biblio/20726400}, journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 792,
place = {United States},
year = {Thu Oct 06 00:00:00 EDT 2005},
month = {Thu Oct 06 00:00:00 EDT 2005}
}