Double-longitudinal spin asymmetry in single-inclusive lepton scattering at NLO

We calculate the double-spin asymmetries ALL for the processes N→ h X and N→ jet\, X at next-to-leading order accuracy in perturbative QCD. We compare our theoretical results for ALL to data from the SLAC E155 experiment, finding only partially satisfactory agreement. We conclude that measurements of ALL and the relevant polarized and unpolarized cross sections should be performed at the present-day fixed-target lepton scattering experiments, as well as at a future electron ion collider, in order to verify our understanding of this process. We present predictions of the longitudinal double-spin asymmetries for these experiments.