3 years ago

# Determination of the proton spin structure functions for $0.05<{Q}^{2}<5\phantom{\rule{0.16em}{0ex}}{\mathrm{GeV}}^{2}$ using CLAS

The basic properties of the proton, the lightest baryon, are determined by its quark and gluon composition. In particular, its spin of $\mathrm{ħ}/2$ has been a challenge to understand in terms of the proton’s constituents. The comprehensive results presented here are based on measurements with high precision and dense kinematic coverage carried out with the CLAS detector at Jefferson Lab. They provide new insight into the proton substructure at resolutions on the length scale of the whole nucleon down to the quark level. A variety of strong interaction models are tested with these new data, to further constrain the quark and gluon contribution to the proton spin.