Speaker: Karoly BANICZ
Title
The NA60 experiment. First results and prospects
Abstract
The NA60 experiment is completing the construction of a silicon pixel telescope for the accurate measurement of dimuon production in collisions of protons and ions with nuclear targets, at top CERN SPS energies. It complements the dimuon spectrometer previously used by the NA50 experiment by measuring the position and momentum of tracks in the vertex region, inside a 2.5 T magnetic field. Preliminary results show that this vertex spectrometer vastly improves the dimuon mass resolution with respect to previous measurements. Its excellent vertex resolution allows us to tag the events according to the impact parameter of the muons and thereby distinguish displaced muons of charmed meson decays from prompt dimuons. The data collected in 2002 confirm the expected performance in terms of dimuon mass resolution and vertex resolution, besides showing that the detector's phase space coverage now extends to remarkably low transverse momenta even at low dimuon masses. As a by-product of the 2002 runs, we have also measured the charged particle rapidity densities, in Pb-Pb collisions at 20 and 30 GeV/nucleon, versus the centrality of the interactions. The run with high energy In-In collisions (Sept-Oct 2003), with the complete vertex spectrometer, will allow us to study the physics mechanisms behind charmonia production and suppression, identify the origin of the excess seen in the production of intermediate region dimuons, measure the yield of open charm production, and study the properties of light vector mesons in a dense medium.

Slides