  In order to understand the gluon contribution to the nucleon spin, some
experiments can study the production of hadrons at high transverse momemtum
from lepton-nucleon or nucleon-nucleon scattering. RHIC has recently measured
such double spin asymmetries $A_{LL}(p_T)$ for pion production at high center
of mass energies, and inclusion of its data to global fits based on NLO
collinear pQCD calculations gives some constraints on the gluon polarization in
the range $0.05<x_g<0.2$.
  To complement these results at COMPASS range, we will present preliminary
COMPASS results on double longitudinal spin asymmetries $A_{LL}(p_T)$ for
single hadron production measured on deuteron and proton target at $Q^2<1$
GeV$^2$, $p_T>1$ GeV/c and center of mass energy $\sqrt{s}\approx 18$ GeV. All
COMPASS data taken from 2002 to 2011 by scattering 160 GeV polarized muons on
longitudinally polarized $^6$LiD and NH$_3$ targets have been used, and the
number of hadrons collected with $p_T>1$ GeV/c for this analysis amounts to
about 10 millions. The obtained asymmetries will be compared to theoretical
predictions of at NLO without gluon resummation calculation.
