Probing dense QCD matter in the laboratory: The CBM experiment at FAIR

The Facility for Antiproton and Ion Research (FAIR) in Darmstadt will provide unique research opportunities for the investigation of fundamental open questions related to nuclear physics and astrophysics, including the exploration of QCD matter under extreme conditions, which governs the structure and dynamics of cosmic objects and phenomena like neutron stars, supernova explosions, and neutron star mergers. The physics program of the Compressed Baryonic Matter (CBM) experiment is devoted to the production and investigation of dense nuclear matter, with a focus on the high-density equation-of-state (EOS), and signatures for new phases of dense QCD matter. According to the present schedule, the CBM experiment will receive the first beams from the FAIR accelerators in 2025. This article reviews promising observables, outlines the CBM detector system, and presents results of physics performance studies.Comment: 16 pages, 13 figures. Physica Scripta 202

CBM Experiment local and global implications

The research area of the compressed baryonic matter - CBM experiment (FAIR/GSI in Darmstadt) is sub-nuclear physics, thus hadron-baryon and quark-gluon, and the essence of phase transitions in the area of hot nuclear matter, and dense strongly interacting matter. Our interest in this paper are mainly considerations on the impact of such large infrastructural experiments and possibilities they give to local, smaller but very active, university based research groups and communities. Research and technical input from such groups is depicted on the background of the CBM detector infrastructure and electronic instrumentation just under design and test fabrication for this experiment. An essential input to this research originates from Poland via the agreed  in-kind contribution. The areas of expertise of these groups are: superconductivity, structural large scale cabling, precision machined parts, RF and microwave technology, analog and advanced digital electronics, distributed measurement and control systems, etc

J/[phi] level one trigger based on the Cellular Automaton method for CBM experiment

Głównym tematem pracy jest selekcja zdarzeń zawierających mezon J /ip przy użyciu Detektora Promieniowania Przejścia. Stworzone procedury działają na niskim poziomie (Poziom 1) systemu akwizycji danych eksperymentu Compressed Baryonic Matter. Na potrzeby poszukiwania sygnatury mezonu stworzono dedykowany algorytm rekonstrukcyjny. Jako sygnaturę wybrano parę e+e_ z pędem poprzecznym każdej cząstki pt > 1 GeV/c i o masie niezmienniczej w okolicach 3.1 GeV/c2. Algorytm rekonstrukcyjny bazuje na idei Automatu Komórkowego, optymalnej dla równoległego przetwarzania danych. Podczas selekcji, zdarzenia pozbawione interesujących informacji są odrzucane a te zawierające sygnaturę rozpadu J/ip są akceptowane. Algorytm rekonstruuje tory wysokopędowych (p > 1 GeV/c) cząstek z pojedynczego centralnego zderzenia Au+Au przy energii 25 GeV/nukleon z wydajnością 92.6% w czasie 0.24 s na standardowym. 3-gigahercowym procesorze klasy Pentium 4. Dla zderzeń peryferyjnych przy tej samej energii, wydajność dla wysokopędowych cząstek wynosi 89.7% a czas jednego zdarzenia to 0.05 s. Wyniki pokazują, że oparta na sygnaturach selekcja zdarzeń pozwala na redukcję ilości zdarzeń tła dla kolizji peryferyjnych o czynnik 1000. przepuszczając 1 zdarzenie tła na 1000 przy zachowaniu 11.7 % zdarzeń z sygnałem z rozpadu J/ip . Oferuje 1000 razy więcej czasu dla systemów analizy wyższego rzędu na przeprowadzenie dodatkowych operacji w trybie on-line

The high-rate data challenge: computing for the CBM experiment

The Compressed Baryonic Matter experiment (CBM) is a next-generation heavy-ion experiment to be operated at the FAIR facility, currently under construction in Darmstadt, Germany. A key feature of CBM is very high interaction rate, exceeding those of contemporary nuclear collision experiments by several orders of magnitude. Such interaction rates forbid a conventional, hardware-triggered readout; instead, experiment data will be freely streaming from self-triggered front-end electronics. In order to reduce the huge raw data volume to a recordable rate, data will be selected exclusively on CPU, which necessitates partial event reconstruction in real-time. Consequently, the traditional segregation of online and offline software vanishes; an integrated on- and offline data processing concept is called for. In this paper, we will report on concepts and developments for computing for CBM as well as on the status of preparations for its first physics run

Status of the CBM experiment

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 pro-gram 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 identifi-cation, hadron/time-of-flight measurement, electromagnetic and zero-degree calorimetry, in terms of prototypes and expected physics performance. The concept and develop-ment status of CBM’s central detector, the Silicon Tracking System STS are presented in somewhat more detail.