Recent Spin Structure Function Measurements from CLAS at Jefferson Laboratory
2018 September 20
2018 November 23
The polarized electron accelerator at Jefferson Laboratory (JLab) in Newport News, Virginia, USA yields a robust program for the study of the spin physics of the nucleon. The CLAS detector and longitudinally polarized target in Hall-B at JLab were employed in multiple measurements of spin-structure functions for the proton and neutron in the resonance and DIS regions at beam energies of up to 6 GeV. Recently published results from the EG1 experiment present extensive measurements of the g1 and g2 structure functions for the proton over a wide kinematic range (0.05 < Q^2 < 5 GeV^2 and 1.08 < W < 3 GeV). These data, together with data from the related EG4 and EG1-DVCS experiments in Hall-B, help constrain global models of structure functions, virtual photon asymmetries, and parton helicity distributions, and provide more precise values of higher-twist matrix elements in the framework of the Operator Product Expansion.