The NA60+ project aims at proposing an experiment at the CERN SPS to study dilepton and heavy-quark production in nucleus-nucleus and proton-nucleus collisions, with a beam energy scan. It is one of the projects followed by the Physics Beyond Colliders initiative.
Tracks produced in the interaction vertex are reconstructed in a vertex telescope immersed in a 1.5 T dipole field. An absorber filters out the hadrons, and muon tracks are then identified and reconstructed in a spectrometer, composed of six tracking stations and a toroidal magnet. A second absorber further reduces the contamination from the surviving hadronic background.
Tracks reconstructed in the muon spectrometer are matched in momentum and coordinates to the corresponding tracks in the vertex spectrometer. With this procedure, a resolution of a few MeV can be reached for the reconstruction of the ω→μμ decay, and of a few tens MeV for the J/ψ→μμ channel