Large analyzing power in inclusive π± production at high xF with a 22-GeV/c polarized proton beam

The analyzing power, A_N, in inclusive charged-pion production has been measured using a ∼22-GeV/c transversely-polarized proton beam on a carbon target. A large A_N was found for x_F>0.5 and for 0.6<p_T<1.2 GeV/c, with similar magnitudes and opposite sign for π⁺ and π^-. This mirror behavior and the magnitudes are similar to π^± production from 200-GeV/c polarized protons on a hydrogen target. The analyzing power for inclusive proton production has also been measured and is consistent with zero.