Speaker
Mr
Hiroki MATSUDA
(Yamagata University)
Description
We present recent COMPASS results on the longitudinal spin structure of the nucleon.
Results from measurements of the gluon helicity Delta G (x) from various channels are shown.
We recently analysed longitudinal double spin asymmetry A_LL(pT) for single hadron production with high-pT hadrons in the low Q2 regime using all COMPASS data. LiD and NH3 were used as polarized deuteron and proton targets. The asymmetries, which are almost consistent with zero,
are compared to theoretical predictions with various Delta G hypotheses.
The latest data on the proton spin structure function g1 in the DIS regime extend
the kinematic domain towards a smaller value of the Bjorken scaling variable x (0.0036)
and higher values of Q2 (up to 100 (GeV/c)2). The data are used in a
global QCD NLO fit of polarized DIS world data to constrain the value of the quark
spin contribution Delta Sigma to the nucleon spin. The dominant uncertainty results
from the choice of the functional forms and in particular of the one taken for the
gluon spin contribution Delta G(x).
Primary author
Mr
Hiroki MATSUDA
(Yamagata University)
