Cosmic Matter in the Laboratory: The CBM Experiment at FAIR

Abstract

The Compressed Baryonic Matter (CBM) experiment is one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR), which presently is under construction adjacent to GSI in Darmstadt, Germany. CBM at FAIR is part of a worldwide research program devoted to the creation and study of extremely hot and dense nuclear matter in the laboratory. In heavy-ion collisions at very high beam energies, as provided by the Relativistic Heavy Ion Collider at BNL in the United States or by the Large Hadron Collider at CERN in Switzerland, elementary matter at extremely high temperatures is created, more than hundred-thousand times hotter than the core of our sun. Under such conditions matter is converted into a plasma that consists of quarks and gluons. This plasma is a mixture of elementary matter and antimatter particles, similar to the primordial soup in the early universe about a microsecond after the big bang. In heavy-ion collisions at lower bombarding energies, as available at the SPS at CERN and at the SIS100 accelerator of FAIR, nuclear matter is strongly compressed. The matter density in the collision zone of two heavy nuclei exceeds more than five times the density of an atomic nucleus. In nature, such densities are expected to exist in the core of neutron stars.