J/ Psi in pA : Performance of the First Level Trigger of Hera-B and Nuclear Effects in J/Psi Production

Abstract

The research for this thesis was done at the Hera-B experiment at Desy, Hamburg. This experiment is a fixed-target hadronic B-factory, built for a first measurement of CP violation. It can be considered as a prototype of future LHC experiments.

The thesis consists of two, essentially independent parts. The first part is a description and a detailed analysis of the performance of the First Level Trigger. The First Level Trigger is a network of custom-made processor boards, designed to perform a full mass reconstruction of J/psi candidates. In this thesis we analysis the resolution and efficiency for J/psi->e+e- decays and describe several hardware tests.

The second part is an analysis of nuclear effects in the production of J/psi. It can be considered as a pioneering study of effects which will be explored at Hera-B with high precision in the near future. The focus is on the measurement of the dependence of the J/psi production cross section on the size of the target nucleus. Other issues, such as transverse momentum broadening and associated particle production are also addressed.