Abstract
Charmonium is one of the most interesting, yet most challenging observables for the CBM experiment. CBM will try to measure charmonium in the di-muon decay channel in heavy-ion collisions close to or even below the kinematic threshold for elementary interactions. The expected signal yield is consequently extremely low - less than one in a million collisions. CBM as a high-rate experiment shall be able to cope with this, provided a suitable software trigger can be implemented for online data selection. Since the latter will be perperformed exclusively on CPU, the performance of the algorithm is crucial for the maximal allowed interaction rate – and thus the sensitivity – and/or for the size of the CBM online cluster FLES (First-Level Event Selector). In this report we discuss the CBM charmonium trigger, its implementation on the FLES, and its performance.
Highlights
CBM is a heavy-ion experiment currently under construction at the FAIR centre in Darmstadt, Germany
One of the most challenging observables for CBM is the measurement of charmonium close to its production threshold, where the cross section is extremely small - less than one J/ψ is expected in a million collisions
Because of the high rates and complex trigger signatures, which are difficult to implement in hardware, CBM chose a readout concept based on free-running, self-triggered front-end electronics
Summary
CBM is a heavy-ion experiment currently under construction at the FAIR centre in Darmstadt, Germany. The identification of muons in CBM will be performed by the muon system MUCH, an active absorber system consisting of alternating absorber and detection layers, placed downstream of the dipole magnet hosting the main tracking system STS (Fig. 1, left). The trajectories inside the system can be approximated by straight lines These properties determine the strategy for track reconstruction detailed in the following: we look for tracks registered in all stations of the system pointing back to the target centre. In the ideal CA all segment computations would be done independently It would be impractical from the performance point of view, not to take into account the fact that the amount of hits registered by a detecting station rapidly decreases with distance from the target.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call