Measurement of the analyzing power in the Primakoff process with a high-energy polarized proton beam

The analyzing power (spin-dependent azimuthal asymmetry) has been observed for the first time in the nuclear Coulomb coherent production process, the ''Primakoff process,'' with the use of the newly constructed 185-GeV/c Fermilab polarized proton beam. We have observed a large asymmetry of this process in the regions of ?t2?<0.001 (GeV/c)2 and 1.36pi0+p