Transverse Momentum Dependent Distributions in Hadronic Collisions:   p(transv. polarized) p --> D + X and p(transv. polarized) p --> gamma + X
  Our understanding of the transverse spin structure of hadrons might definitely get improved by the information we gather on transverse momentum dependent (TMD) distributions. These new functions could also be crucial for a description of the observed transverse single spin asymmetries (SSA). In a hard scattering model for inclusive hadronic reactions, based on a generalized QCD factorization scheme, many mechanisms - namely the Sivers, Collins, Boer-Mulders effects - might contribute to a SSA. We show how the k_T dependent phases arising from the partonic kinematics together with a suitable choice of experimental configurations could help in disentangling the above mentioned effects. We discuss their potential role in two inclusive hadronic processes: heavy meson and photon production in pp and p pbar collisions. 
U. D'Alesio and F. Murgia (University and INFN, Cagliari, Italy)