Examination of direct-photon and pion production in proton-nucleon   collisions
  We present a study of inclusive direct-photon and pion production in hadronic interactions, focusing on a comparison of the ratio of gamma/pi0 yields with expectations from next-to-leading order perturbative QCD (NLO pQCD). We also examine the impact of a phenomenological model involving k_T smearing (which approximates effects of additional soft-gluon emission) on absolute predictions for photon and pion production and their ratio. 
L. Apanasevich, M. Begel, C. Bromberg, T. Ferbel, G. Ginther, J.   Huston, S.E. Kuhlmann, P. Slattery, M. Zielinski, V. Zutshi