Hard-scattering scaling laws for single-spin production asymmetries

The extraction of a scaling law of the form (({ital p}{sub {ital T}}{sup 2}+{mu}{sup 2})/{mu}{ital p}{sub {ital T}}){ital A}{sub {ital N}}{congruent}{ital g}({ital x}{sub {ital T}}) (where {ital x}{sub {ital T}}=2{ital p}{sub {ital T}}/ {radical}{ital s} ) from data on a single-spin production asymmetry such as {ital A}{sub {ital N}d}{sigma}({ital pp}{sub {up arrow}}{r arrow}{pi}{sup 0}{ital X}) at large transverse momentum can be used to argue for an underlying hard-scattering'' mechanism. Data from the upcoming Fermilab polarized beam experiment (E-704) can be used to test the scaling hypothesis.