Unintegrated parton distributions and meson production in hadronic collisions

Abstract

The inclusive distributions of gluons and pions for high-energy NN collisions are calculated. The results for several unintegrated gluon distributions (UGD's) from the literature are compared. We find huge differences in both rapidity and $p_t$ of gluons and $\pi$'s in NN collisions for different models of UGD's. The Karzeev-Levin UGD gives good description of momentum distribution of charged hadrons at midrapidities. We find, however, that the gluonic mechanism discussed does not describe the inclusive distributions of charged particles in the fragmentation region. Some of the missing mechanisms are calculated with the help of unintegrated parton distributions being solutions of the Kwieciński CCFM equations. We predict an asymmetry in ${\pi }^{+}$ and ${\pi }^{-}$ production which could be studied by the BRAHMS collaboration at RHIC.

Comments: 9 pages, a talk at the workshop "Hot and dense nuclear matter in relativistic heavy ion collisions", Budapest, Hungary, March 24-27, 2004