Single-spin asymmetries in inclusive charged pion production by transversely polarized antiprotons

The analyzing power A(N) in inclusive pi(-) and pi(+) production has been measured with a 200 GeV/c transversely polarized antiproton beam over a wide x(f) range (0.2 less than or equal to x(f) less than or equal to 0.9) and at moderate p(T) (0.2 less than or equal to p(T) less than or equal to 1.5 GeV/c). The asymmetry A(N) increases with increasing x(F) from zero to large positive values for pi(-,)s, and decreases from zero to large negative values for pi(+,)s. A threshold for the onset of the asymmetry is observed about p(T) similar to 0.5 GeV/c, below which A(N) is essentially zero and above which A(N) increases (decreases) with p(T) for pi(-,)s (pi(+,)s) in the covered p(T) range.