The compressed baryonic matter (CBM) experiment at the future FAIR accelerator facility near Darmstadt, Germany, aims at the investigation of baryonic matter at highest net baryon densities but moderate temperatures, by colliding heavy-ions at beam energies from 10 to 45 A GeV. The research program comprises the exploration of some basic landmarks of the QCD phase diagram like transitions from hadronic to partonic phase, the region of first order de-confinement as well as chiral phase transition, and the critical end point. The proposed key observables include the measurement of low mass vector mesons and charmonia, which can be detected via their decay into the di-lepton channel. As the decayed leptons leave the hot and dense fireball without further interactions, hence they provide almost unscathed information about the interior of the collision zone where they are being created. In this paper, we discuss the physics motivation, detector concepts, and the feasibility studies in the di-muon measurements for central Au + Au collisions, with a special reference to the detailed simulation activities performed by the CBM muon group.We also discuss the R&D activities of detector in brief.
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-…
The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt is designed to investigate the properties of high-density QCD matter with multi-differential measurements of hadrons and leptons, including rare probes like multi-strange anti-hyperons and charmed particles. The research program covers the study of the high-density equation-of-state of nuclear matter, and the exploration of the QCD phase diagram at large baryon-chemical potentials, including the search for quark matter and the critical endpoint of a hypothetical 1st order …
The stability of triple GEM detector setups in an environment of high energetic showers is studied. To this end the spark probability in a shower environment is compared to the spark probability in a pion beam.
In order to provide particle identification (PID) of charged hadrons at the future high-rate Compressed Baryonic Matter (CBM) experiment the TOF group has developed a large-area Time-of-Flight (ToF) wall equipped with Multi-gap Resistive Plate Chambers (MRPC) capable to operate at incident particle fluxes of up to 30 kHz/cm$^2$. Prior to its destined operation at the Facility for Antiproton and Ion Research (FAIR) - starting in 2025 - this high-rate timing MRPC technology will be used for physics research at two scientific pillars of the FAIR Phase-0 program: the end-cap TOF upgrade of the STA…
The Compressed Baryonic Matter experiment at FAIR will investigate the QCD phase diagram in the region of high net-baryon densities. Enhanced production of strange baryons, such as the most abundantly produced $Λ$ hyperons, can signal transition to a new phase of the QCD matter. In this work, the CBM performance for reconstruction of the $Λ$ hyperon via its decay to proton and $π^{-}$ is presented. Decay topology reconstruction is implemented in the Particle-Finder Simple (PFSimple) package with Machine Learning algorithms providing efficient selection of the decays and high signal to backgrou…
Characteristics of triple GEM detector have been studied systematically. The variation of the effective gain and energy resolution of GEM with variation of the applied voltage has been measured with Fe55 X-ray source for different gas mixtures and with different gas flow rates. Long-term test of the GEM has also been performed.
The mission of the Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt is to explore the QCD phase diagram at high net baryon densities likely to exist in the core of neutron stars. The CBM detector system is designed to perform multi-differential measurements of hadrons and leptons in central gold-gold collisions at beam energies between 2 and 11 A GeV with unprecedented precision and statistics. In order to reduce the systematic errors of the lepton measurements, which generally suffer from a large combinatorial background, b…
We advocate for an active US participation in the international collaboration of the CBM experiment that will allow the US nuclear physics program to build on its successful exploration of the QCD phase diagram, use the expertise gained at RHIC to make complementary measurements at FAIR, and contribute to achieving the scientific goals of the beam energy scan (BES) program.
The future Facility for Antiproton and Ion Research (FAIR) is an accelerator-based international center for fundamental and applied research, which presently is under construction in Darmstadt, Germany. An important part of the program is devoted to questions related to astrophysics, including the origin of elements in the universe and the properties of strongly interacting matter under extreme conditions, which are relevant for our understanding of the structure of neutron stars and the dynamics of supernova explosions and neutron star mergers. The Compressed Baryonic Matter (CBM) experiment …
The Compressed Baryonic Matter Experiment (CBM) is one of the core experiments of the future FAIR facility (Darmstadt/Germany). The fixed-target experiment will explore the phase diagram of strongly interacting matter in the regime of high net baryon densities with numerous rare probes. The Micro Vertex Detector (MVD) will determine the secondary decay vertex of open charm particles with $\sim 50~\rm μm$ precision, contribute to the background rejection in dielectron spectroscopy, and help to reconstruct neutral decay products of strange particles by means of missing mass identification. The M…
The Compressed Baryonic Matter (CBM) experiment is being planned at the international research center FAIR, under realization next to the GSI laboratory in Darmstadt, Germany. Its physics programme addresses the QCD phase diagram in the region of highest net baryon densities. Of particular interest are the expected first order phase transition from partonic to hadronic matter, ending in a critical point, and modifications of hadron properties in the dense medium as a signal of chiral symmetry restoration. Laid out as a fixed-target experiment at the heavy-ion synchrotrons SIS-100/300, the dete…
Non-statistical event-by-event fluctuations are considered an important signal for the critical endpoint of the QCD phase diagram. Event-by-event fluctuations of different observables are thus investigated in detail in current experiments. In this contribution, a study of the centrality dependence of event-by-event fluctuations of particle yield ratios by the NA49 experiment in Pb+Pb collisions at 158A GeV beam energy is presented for the first time. An increase of the absolute values of dynamical fluctuations towards lower centralities is observed. The influence of resonance decays will be di…
The Facility for Antiproton and Ion Research (FAIR), an international accelerator centre, is under construction in Darmstadt, Germany. FAIR will provide high-intensity primary beams of protons and heavy-ions, and intense secondary beams of antiprotons and of rare short-lived isotopes. These beams, together with a variety of modern experimental setups, will allow to perform a unique research program on nuclear astrophysics, including the exploration of the nucleosynthesis in the universe, and the exploration of QCD matter at high baryon densities, in order to shed light on the properties of neu…
The Compressed Baryonic Matter (CBM) experiment will investigate high-energy heavy-ion collisions at the international Facility for Antiproton and Ion Research (FAIR), which is under construction in Darmstadt, Germany. The CBM research program is focused on the exploration of QCD matter at neutron star core densities, such as study of the equation-of-state and the search for phase transitions. Key experimental observables include (multi-) strange (anti-) particles, electron-positron pairs and dimuons, particle correlations and fluctuations, and hyper-nuclei. In order to measure these diagnosti…
The Compressed Baryonic Matter (CBM) experiment planned at Facility for Antiproton and Ion Research (FAIR) will provide a major scientific effort for exploring the properties of strongly interacting matter in the high baryon density regime. One of the important goal behind such experiment is to precisely determine the equation of state (EOS) for the strongly interacting matter at extreme baryon density. In this paper, we have used a thermal model EOS incorporating excluded volume description for the hot and dense hadron gas (HG). We then predict different particle ratios and the total multipli…
Hypernucleus production in p+Au reactions at the FAIR facility
Naresuan University（纳瑞宣大学）；Suranaree University of Technology（素拉那里理工学院）；GSI Helmholtzzentrum für Schwerionenforschung GmbH（GSI亥姆霍兹重离子研究中心有限公司）；Frankfurt Institute for Advanced Studies（法兰克福高等研究院）；Goethe-Universität Frankfurt（法兰克福歌德大学）
The CBM experiment will investigate heavy-ion collisions at beam energies from 8 to 45 AGeV at the future accelerator facility FAIR. The goal of the experiment is to study the QCD phase diagram in the region of moderate temperatures and highest net-baryon densities in search of the first-order phase transition from confined to deconfined matter at the QCD critical point. To do so, CBM aims to measure rare hadronic, leptonic and photonic probes among them open charm. In order to reject the rich background generated by the heavy ion collisions, a micro vertex detector (MVD) providing an unpreced…
The fundamental properties of dense nuclear matter, as it exists in the core of massive stellar objects, are still largely unknown. The investigation of the high-density equation of state (EOS), which determines mass and radii of neutron stars and the dynamics of neutron star mergers, is in the focus of astronomical observations and of laboratory experiments with heavy-ion collisions. Moreover, the microscopic degrees-of-freedom of strongly interacting matter at high baryon densities are also unknown. While Quantum-Chromo-Dynamics (QCD) calculations on the lattice find a smooth chiral crossove…
Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition be…
