Forward charge asymmetry in low-P T photoproduction of hadrons

Abstract

The charged particle asymmetry, (n+−n−)/(n++n−), in inclusive photoproduction of charged particles on protons has been studied as a function ofxF andpT in the rangesxF>0 and 0<pT<2 GeV/c and for photon energies in the range 65<Eγ<175 GeV. The asymmetry is found to be positive and decreasing withEγ. Asymmetries of π's and K's in the final state have been obtained separately. Data from a carbon target show a significantly lower asymmetry. These results have been compared with a parton, recombination model which provides a qualitative explanation for the asymmetry and itsxF andEγ dependences. The model also gives a qualitative understanding of the lower asymmetry seen with the nuclear target.