Search for the quark-gluon-plasma in the NA60 experiment at the SPS/CERN

Full text: The study of high energy heavy ion collisions is presently in a very interesting phase. Among the most exciting observations made by the SPS experiments at CERN are the NA50 measurements on the centrality dependence of the J/ψ suppression pattern and on the enhancement of the intermediate mass dimuon production, a possible indication of thermal dimuons. NA60, a new SPS experiment, will take data with proton and heavy ion beams between 2001 and 2003, extending the NA50 physics program by means of two new silicon detectors placed in the target region: a beam tracker and a silicon tracking telescope. This vertex spectrometer will enable NA60 to study the production of prompt dimuons, with vastly improved mass resolution, and of muons originating from the decay of charmed mesons, by measuring the impact parameter of the muon tracks. NA60 will study the pattern of J/ψ and ψ' production in collisions of indium nuclei, hopefully confirming that the observations done with Pb-Pb collisions signal the formation of a deconfined quark-gluon phase at SPS energies, and providing fundamental information on the physical mechanisms driving the phase transition. NA60 will also clarify the origin of the dimuon excess seen in the intermediate mass region, maybe due to thermal dimuon production, and measure the yield of charmed mesons produced in nuclear collisions. In this talk, I will explain the NA60 detector concept, describe the detectors (including results from feasibility tests), and will present the physics performance capability of the experiment. (author)