The inclusive double-spin asymmetry, View the MathML sourceA1p, has been measured at COMPASS in deep-inelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range View the MathML sourceQ2>1(GeV/c)2, 0.004<x<0.70.004<x<0.7 and improve the statistical precision of View the MathML sourceg1p(x) by a factor of two in the region x<0.02x<0.02. The new proton asymmetries are combined with those previously published for the deuteron to extract the non-singlet spin-dependent structure function View the MathML sourceg1NS(x,Q2). The isovector quark density, Δq3(x,Q2)Δq3(x,Q2), is evaluated from a NLO QCD fit of View the MathML sourceg1NS. The first moment of Δq3Δq3 is in good agreement with the value predicted by the Bjorken sum rule and corresponds to a ratio of the axial and vector coupling constants View the MathML source|gA/gV|=1.28±0.07(stat.)±0.10(syst.).
The spin-dependent structure function of the proton g(1)(p) and a test of the Bjorken sum rule RID A-2616-2008 RID D-4627-2011
PANZIERI, Daniele;
2010-01-01
Abstract
The inclusive double-spin asymmetry, View the MathML sourceA1p, has been measured at COMPASS in deep-inelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range View the MathML sourceQ2>1(GeV/c)2, 0.004I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
