Charmed Meson Production in Proton - (ANTI)PROTON Collisions.pdf

a r X i v : h e p - p h / 0 6 0 8 2 0 2 v 1 1 8 A u g 2 0 0 6 February 2, 2008 6:56 WSPC/Guidelines-IJMPA luszczak International Journal of Modern Physics A c? World Scientific Publishing Company CHARMED MESON PRODUCTION IN PROTON - (ANTI)PROTON COLLISIONS ? MARTA LUSZCZAK University of Rzeszo?w, ul. Rejtana 16c PL-35-959 Rzeszo?w, Poland ANTONI SZCZUREK Institute of Nuclear Physics PAN, ul. Radzikowskiego 152 PL-31-342 Cracow, Poland and University of Rzeszo?w, ul. Rejtana 16c PL-35-959 Rzeszo?w, Poland Received (Day Month Year) Revised (Day Month Year) 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 com- pare results obtained with on-shell and off-shell matrix elements and kinematics. The results are compared with recent experimental results of the CDF collaboration. 1. Introduction The heavy quark-antiquark production in hadroproduction is known as one of the crucial tests of conventional gluon distributions within a standard factorization approach. At high energies one tests gluon distributions at low values of longitu- dinal momentum fraction. Standard collinear approach does not include transverse momenta of initial gluons, the method to include transverse momenta is kt - factor- ization approach1,2,3. In the first step of our approach the single particle spectra of charmed quarks and antiquarks are obtained assuming gluon-gluon fusion4. Differ- ent unintegrated gluon distributions from the literature are used5,6,7,8,9. To obtain the single particle spectra of meson from those of quarks/antiquarks a standard hadronization procedure with Peterson fragmentation function is applied. Conclu- sions about unintegrated gluon distributions are drawn. 1 February 2, 2008 6:56 WSPC/Guidelines-IJMPA luszczak 2 M. Luszczak and A. Szczurek h2 κ21t = 0 (collinear) κ22