New measurements of proton polarized structure functions in charged current processes at DESY HERA

Predictions for longitudinal spin asymmetries which single out new polarized nucleon structure functions in deeply inelastic charged current interactions at DESY HERA energies are given, exploiting their interpretation in terms of polarized quark distributions. These asymmetries turn out to be large and allow a measurement of the new polarized structure functions g1W and g5W, which would add valuable tests and information on the spin content of quarks inside a polarized proton. We also show that single-spin asymmetries in neutral current interactions are very small.