TY - JOUR
T1 - Direct estimate of the gluon polarization in the nucleon
AU - Ellis, John
AU - Karliner, Marek
N1 - Funding Information:
M.K. wishes to thank Cavendish Laboratory at the University of Cambridge, UK, for hospitality during sabbatical leave of absence when this research was carried out. The research of one of us (M.K.) was supported in part by a grant from the Israel Science Foundation administered by the Israel Academy of Sciences and Humanities. We thank Elke Aschenauer, Colin Bernet, Catarina Quintans, Ewa Rondio, Naohito Saito and Robert Thorne for discussions and correspondence.
PY - 2006/3/21
Y1 - 2006/3/21
N2 - We make a first crude direct estimate of the net gluon polarization in the proton, ΔG, combining data on the asymmetries in high-pT hadron production from the HERMES, SMC and COMPASS collaborations. Although these data sample a restricted range of x, they provide no hint that ΔG is large. Fixing the normalizations of different theoretical parametrizations using the hadron asymmetry data, we find typical central values of ΔG ∼ 0.5, with uncertainties of similar magnitude. Values of ΔG ≥ 2 are disfavored by Δχ2 ∼ 9 to 20, depending on the parametrization used.
AB - We make a first crude direct estimate of the net gluon polarization in the proton, ΔG, combining data on the asymmetries in high-pT hadron production from the HERMES, SMC and COMPASS collaborations. Although these data sample a restricted range of x, they provide no hint that ΔG is large. Fixing the normalizations of different theoretical parametrizations using the hadron asymmetry data, we find typical central values of ΔG ∼ 0.5, with uncertainties of similar magnitude. Values of ΔG ≥ 2 are disfavored by Δχ2 ∼ 9 to 20, depending on the parametrization used.
KW - Axial anomaly
KW - Gluons
KW - Nucleon spin decomposition
KW - Nucleon strangeness
KW - Polarized structure function
KW - Quantum chromodynamics (QCD)
UR - https://www.scopus.com/pages/publications/33645360647
U2 - 10.1142/S0217732306019761
DO - 10.1142/S0217732306019761
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AN - SCOPUS:33645360647
SN - 0217-7323
VL - 21
SP - 721
EP - 728
JO - Modern Physics Letters A
JF - Modern Physics Letters A
IS - 9
ER -