Status of the CBM experiment

GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany

^a e-mail: J.Heuser@gsi.de

Published online: 29 May 2015

Abstract

The Compressed Baryonic Matter (CBM) experiment at the Facility for Anti-Proton and Ion Research (FAIR) will explore the phase diagram of strongly interacting matter at highest net baryon densities and moderate temperatures. The CBM physics program will be started with beams delivered by the SIS 100 synchrotron, providing energies from 2 to 11 GeV/nucleon for heavy nuclei, up to 14 GeV/nucleon for light nuclei, and 29 GeV for protons. The highest net baryon densities will be explored with ion beams up to 45 GeV/nucleon energy delivered by SIS 300 in the next stage of FAIR. Collision rates up to 10⁷ per second are required to produce very rare probes with unprecedented statistics in this energy range. Their signatures are complex. These conditions call for detector systems designed to meet the extreme requirements in terms of rate capability, momentum and spatial resolution, and a novel DAQ and trigger concept which is not limited by latency but by throughput. The article discusses the development status of the CBM sub-systems for charged particle tracking, vertex detection, electron/muon identification, hadron/time-of-flight measurement, electromagnetic and zero-degree calorimetry, in terms of prototypes and expected physics performance. The concept and development status of CBM’s central detector, the Silicon Tracking System STS are presented in somewhat more detail.