Measurement of the analyzing power of high-transverse-momentum charged hadrons in proton-nucleus collisions at an energy of 40 GeV

The transverse single-spin asymmetry was measured for charged hadrons (π ±, K ±, p, \(\bar p\)) produced in proton-nucleus collisions. The measurements were performed at the FODS-2 spectrometer by using a polarized proton beam that was accelerated to an energy of 40 GeV at the accelerator of the Institute for High Energy Physics (IHEP, Protvino) and which was made to hit carbon and copper nuclear targets. The data in question were obtained in the range of c.m. angles between 73° and 94° near the central region (−0.01 < x F < 0.27, 0.7 < p T < 3.6 GeV/c). The single-spin asymmetry for π + and K + mesons is significant at high values of p T and moderately small positive values of x F. The analyzing power for other hadrons (π −, K −, p, \(\bar p\)) is compatible with zero in the p T range studied here. The dependence of the analyzing power on the mass number of the target nucleus is insignificant.