Charmonium Production at HERA-B

The talk gives a status report on the Charmonium-production at HERA-B. The reaction under study is Chi_c -> J/Psi + gamma, J/psi -> mumu. Firstly a presentation of previous results in pN-data is given, followed by a look at the different theoretical models for QCD-production. Results are presented from both the second and third reprocessing of the 2000 data-sample. For the second reprocessing we have reconstructed approx. 40 Chi_c Carbon target. A preliminary result of the fraction of directly produced J/Psi and J/Psi produced through radiative Chi_c decay is presented. In the third reprocessing of the data we see approx. 100 Chi_c divided between the Carbon and Titanium wire.


Andreas Christensen