Possible start version of the CBM muon detector system at SIS100

The CBM muon detection system (MuCh) was optimized for nucleus-nucleus collisions at SIS300 beam energies (see [1]). We have investigated the possibility to simplify the setup for measurements of J/ψ mesons in protonnucleus collisions at SIS100 beam energies. Therefore, the performance of the muon detection system has been studied as function of the number of the detector stations for J/ψ measurements in p + Au collisions at 25 AGeV. The simulations are based on a segmentation of the detector layers into pads with a minimum size of 0.28×0.28 cm, and a maximum size of 4.48×4.48 cm, corresponding to a total of 560 000 channels. For full track reconstruction the LIT global tracking package [2] is used. In order to study the sensitivity of the reconstruction algorithm on the number of the detector stations, we removed the hits in each station from the track finding procedure. The signal-tobackground (S/B) ratio and the J/ψ meson reconstruction efficiency or the full and for the reduced systems are shown in fig.1: 1-6 means that hits of all 6 stations are used by the reconstruction procedure; 2-6 means that the hits of the first station were removed from the reconstruction; 3-6 means that the hits of the two first stations were not used in reconstruction, etc.