Charmed Meson Production in Proton - (ANTI)PROTON Collisions
  We discuss and compare different approaches to include gluon transverse momenta for heavy quark-antiquark pair and meson production. The results are illustrated with the help of different unintegrated gluon distributions (UGDF) from the literature. We compare results obtained with on-shell and off-shell matrix elements and kinematics. The results are compared with recent experimental results of the CDF collaboration. 
Marta Luszczak and Antoni Szczurek