Measurement Of Analyzing Powers Of Pi(+) And Pi(-) Produced On A Hydrogen And A Carbon Target With A 22-Gev/C Incident Polarized Proton Beam

The analyzing powers of pi(+) and pi(-) were measured using an incident 22-GeV/c transversely polarized proton beam at the Brookhaven Alternating Gradient Synchrotron. A magnetic spectrometer measured pi(+/-) inclusive asymmetries on a hydrogen and a carbon target. An elastic polarimeter with a CH2 target measured pp elastic-scattering asymmetries to determine the beam polarization using published data for the pp elastic analyzing power. Using the beam polarization determined from the elastic polarimeter and asymmetries from the inclusive spectrometer, analyzing powers A(N) for pi(+/-) were determined in the x(F) and p(T) ranges (0.45-0.8) and (0.3-1.2 GeV/c), respectively. The analyzing power results are similar in both sign and character to other measurements at 200 and 11.7 GeV/c, confirming the expectation that high-energy pion inclusive analyzing powers remain large and relatively energy independent. This suggests that pion inclusive polarimetry may be a suitable method for measuring future beam polarizations at BNL RHIC or DESY HERA. Analyzing powers of pi(+) and pi(-) produced on hydrogen and carbon targets are the same. Various models to explain inclusive analyzing powers are also discussed.