Nuclear dependence asymmetries in direct photon production

We study the nuclear dependences of high-$p_T$ jet cross sections in one photon and one jet production in proton-nucleus collisions. We find that there exist asymmetries between the outgoing jets and photons. A convincing reason responsible for those asymmetries are demonstrated in perturbative QCD. Significant nuclear enhancements are also found in the inclusive jet cross sections.Comment: 9 pages, LaTeX, 5 ps-figure