Recent measurement of {delta}G/G at COMPASS

Journal Article · Thu Oct 06 04:00:00 EDT 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2122209· OSTI ID:20726400

Bernet, C

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.

• OSTI ID: 20726400
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 792; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

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