Recent COMPASS results on the gluon polarization

Journal Article · Mon Mar 23 04:00:00 EDT 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3122152· OSTI ID:21293416

Quintans, Catarina ^[1]

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1. Laboratorio de Instrumentacao e Fisica Experimental de Particulas, LIP-Lisboa (Portugal)

The spin structure of the nucleon is studied in the COMPASS experiment at CERN/SPS, from the collisions of 160 GeV polarized muon beam with a {sup 6}LiD target. The data collected from 2002 to 2006 provide an accurate measurement of longitudinal double spin cross-section asymmetries. The latest results on the gluon polarization, accessed from two independent analyses of photon-gluon fusion selected events, are presented. The study of the open-charm production allows to extract the gluon polarization (in LO QCD) from the measurement of the asymmetry, the value obtained being {delta}g/g -0.49{+-}0.27(stat){+-}0.11(syst), at an average x{sub g} 0.11{sub -0.05}{sup +0.11} and a scale <{mu}{sup 2}> = 13(GeV/c){sup 2}. An alternative and independent way to study the gluon polarization, by studying the high transverse momentum hadron pairs produced, leads to a value {delta}g/g 0.08{+-}0.10(stat){+-}0.05(syst), at x{sub g}{sup a{nu}} 0.082{sub -0.027}{sup +0.041} and <{mu}{sup 2}> = 3(GeV/c){sup 2}.

• OSTI ID: 21293416
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1105; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMMETRY
CERN SPS SYNCHROTRON
COMPTON EFFECT
CROSS SECTIONS
DEUTERIUM TARGET
GEV RANGE
GLUONS
LITHIUM 6 TARGET
MUON BEAMS
MUON REACTIONS
PAIR PRODUCTION
PHOTONS
POLARIZED BEAMS
POLARIZED TARGETS
QUANTUM CHROMODYNAMICS
QUARKS
SPIN
TRANSVERSE MOMENTUM