We present a measurement of the deuteron spin-dependent structure function gd
1 based on
the data collected by the COMPASS experiment at CERN during the years 2002–2004.
The data provide an accurate evaluation for ��d
1 , the first moment of gd
1(x), and for the matrix
element of the singlet axial current, a0. The results of QCD fits in the next to leading
order (NLO) on all g1 deep inelastic scattering data are also presented. They provide two
solutions with the gluon spin distribution function G positive or negative, which describe
the data equally well. In both cases, at Q2 = 3 (GeV/c)2 the first moment of G is found
to be of the order of 0.2 − 0.3 in absolute value. |
