The future Facility for Antiproton and Ion Research (FAIR)


The future international Facility for Antiproton and Ion Research (FAIR) in Darmstadt will open a new era of forefront research in nuclear physics, hadron physics, plasma physics, atomic physics, radiation biophysics, and material research. The FAIR start version will comprise the synchrotron SIS100, a collector ring, a storage ring, and a variety of experimental setups. SIS100 will provide high-intensity primary beams of protons up to 29 GeV, and nuclear beams with kinetic energies of 15 GeV per nucleon. FAIR will generate particle beams of a previously unparalleled intensity and quality. The variety of these particles will be unique: Ions of all the natural elements in the periodic table, as well as antiprotons. Beams of rare isotopes will be selected from nuclear reactions by the Superconducting Fragment Separator, and guided for further investigated to the experimental facilities built and operated by the NUSTAR collaboration. The High-Energy Storage Ring (HESR) will accelerate and cool intense secondary beams of antiprotons, and focus them on the target of the PANDA detector, where hadron physics experiments will be performed. A dedicated cave will host the various detector setups for atomic, plasma, biophysics and material research. The Compressed Baryonic Matter (CBM) and HADES detectors are designed for the investigation of the properties of dense nuclear matter and modifications of hadron properties in the dense nuclear medium, which will be created in energetic nucleus-nucleus collisions. Civil construction is well under way, and the manufacturing and test of the accelerator components is progressing. Installation and commissioning of the experiments is planned for 2022 - 2024, and the first beams from SIS100 are expected for 2025. The layout showing the future facility is depicted in figure below.


The animation showing construction of FAIR can be watched at YouTube.


Physicists from our faculty are strongly involved in three experiments: CBM, HADES and PANDA. Jagiellonian University is a coordinator of Polish Institutions grouped in a consortium Femtophysics and an international shareholder in the FAIR.


On April 23, 2021, a remote Zoom meeting Krakow@FAIR Virtual Workshop was held.

HADES experiment - first running FAIR experiment

High Acceptance Dielectron Spectrometer (HADES) is a first FAIR experiment already existing and located at SIS18. The detector measures particles produced in proton, pion and heavy ion induced reactions on stationary targets made of various atoms (i.e. hydrogen, carbon, gold). The unique feature of the detector is an ability to measure virtual massive photons that converts in a very short time (Heisenberg principle) to electron-positron pairs. The beam particles are provided by SIS18 synchrotron which accelerates charged ions to kinetic energies of 1-2 GeV per nucleon. After completion of the physics programme at SIS18 the detector will be moved to CBM cave to continue measurements at higher beam energies provided by SIS100.


The mission of the experiments is twofold:

  1. Using heavy ion collisions the experiment is studying properties of an exotic form of nuclear matter which is created in course of the reaction for an extremely short glimpse of time (~20 fm/c ≅ 1022s). This piece of matter, called fireball (see picture below), is characterized by a large density (exceeding even 2-3 times density of ordinary nuclear matter) and a temperature reaching up to 1022 Kelvin (kBT= 70 MeV)! The temperature is estimated from the spectral distribution of virtual photons (invariant mass of lepton pairs) measured in the detector. The distribution resembles the radiation emitted from a black body (Planck distribution). The fireball density, and also the temperature of the final stage of the collision (so called freeze-out), was also estimated from the spectra of emitted hadrons (mesons, protons) and showed to be slightly smaller. One should note that similar form of nuclear matter can be created on a macroscopic scale only in collisions of neutron stars.


    The spectra of emitted lepton pairs carry-out also undistorted information of about masses of decaying mother particles and hence can be used to measure in-medium modification of hadron properties like masses and widths. Experiments provides striking evidences that hadrons do change their properties inside dense fireball medium.

  2. Using proton-proton or pion-proton reactions the experiment probes internal structure of baryons measuring mass distribution of virtual photons emitted in transitions between excited and ground states of nucleons. From these measurements one concludes that nucleon looks like a composite object consisting from a quark core (made out of three valence quarks) and a meson “cloud” surrounding the core.


A group of physicist from the Department of Hadron Physics takes part in the HADES experiment since its foundation. The group provided several important components of the HADES detector developed in: the Gasous ionization detectors and the Electronic laboratories of the Cluster of Nuclear Physics Departments. The group takes also active part in the data analysis, specializing on electron-positron pairs and hadron production in proton and pion induced reactions. The HADES experiment is continuously supported by the Polish Science Foundation (NCN) by prestigious grants HARMONIA, HARMONIA and  POLONEZ.


Further recommended reading :

  • HADES Collaboration, "Probing dense baryon-rich matter with virtual photons”, Nat. Phys. 15, 1040–1045 (2019);
  • P. Salabura (Jagielonian U.), J. Stroth (Frankfurt U., Inst. Kernphys. and Darmstadt, GSI and HIC for FAIR, Frankfurt), “Dilepton Radiation from Strongly Interacting Systems”, arXiv:2005.14589 [nucl-ex].


Contact: prof. dr hab. Piotr Salabura

CBM experiment - scientific mission and detector setup

The scientific mission of the CBM experiment is study of the phase diagram of the strongly interacting matter (see figure). Such matter can be created in the laboratory by nucleus-nucleus high energy head on collisions. In particular the CBM research program is foreseen to provide answers to the following fundamental questions:

  • What is the high-density equation-of-state of nuclear matter, which is relevant for our understanding of supernova, the structure of neutron stars, and the dynamics of neutron star mergers?

  • Is there a phase transition from hadronic to quark-gluon matter, a region of phase coexistence, and a critical point? Do exotic phases of strongly interacting matter (QCD matter) like quarkyonic matter exist?

  • Can we find experimental evidence for modification of hadron massed in dense and hot nuclear matter?

  • How far can we extend the chart of nuclei towards the third (strange) dimension by producing single and double hypernuclei (nuclei with strange quarks inside)? Which role hyperons play in the core of neutron stars?


These questions will be addressed by measuring the following observables:

  • The equation-of-state can be studied by measuring (i) the collective flow of identified particles, which is generated by the density gradient of the early fireball, and (ii) by multi-strange hyperons, which are preferentially produced in the dense phase of the fireball via sequential collisions.

  • The existence of a phase transition from hadronic to partonic matter is expected to be reflected in the following observables: (i) the excitation function of multi-strange hyperons, which are driven into equilibrium at the phase boundary; (ii) the excitation function of the invariant mass spectra of lepton pairs which reflect the fireball temperature, and, hence, may reveal a caloric curve and a first-order phase transition; (iii) the excitation function of higher-order event-by-event fluctuations of conserved quantities such as strangeness, charge, and baryon number may be are expected to occur in the vicinity of the critical point (“critical opalescence”).

  • Modifications of hadron properties in dense baryonic matter and the onset of chiral symmetry restoration will affect the invariant-mass spectra of di-leptons, which will be measured both in the electron and the muon channel with unprecedented precision.

  • The discovery of new (double-Λ) hyper-nuclei, and the measurement of their life time will provide information on the hyperon-nucleon and hyperon-hyperon interaction, which will shed light on the hyperon puzzle in neutron stars.

An exhaustive review of the physics of hot and dense strongly interacting matter is presented in Ref. [1]. More information about CBM instrumentation and research program can be found in set of articles [2-4].


The CBM and HADES detector setups are shown in the figure below. The two setups will be operated alternatively. The CBM setup is a fixed target experiment which will be capable to measure hadrons, electrons and muons in heavy-ion collisions over the full FAIR beam energy range. In a central collision of two gold nuclei at FAIR energies, about 700 charged particles are emitted. The tracks of these particles will be measured by a Silicon Tracking System (STS) consisting of 8 layers of double-sided micro-strip sensors located in a magnetic field of a superconducting dipole magnet. Polish groups participating in the CBM experiment have particularly large contribution to STS. A group of physicist from the Department of Hot Matter Physics takes part in development of the CBM experiment since very beginning. The group will provide very important elements of the STS read-out system as well as contribute to design and support of the experimental data base. The project is financed by the Polish Ministry of Science and Higher Education from in-kind contribution to FAIR.

The HADES detector (left) and the CBM experimental setup (right).


[1] B. Friman et al. "CBM Physics Book", 2011.
[2] C. Hohne at al. “The Compressed Baryonic Matter Experiment at FAIR”, Nuclear Physics News, Vol. 16, No. 1, 2006 .
[3] P. Senger (for the CBM Collaboration), arXiv:2005.03321 [nucl-ex].
[4] Ch. Simon, I. Deppner, and N. Hermann (for the CBM collaboration) "The physics program of the CBM experiment", PoS (CPOD2017) 014.


Contact: dr hab. Paweł Staszel, prof. UJ

PANDA experiment - strong interaction studies with antiprotons

PANDA experiment at the high energy antiproton storage ring HESR is dedicated to detailed studies of the structure and interactions of strongly interacting particles, hadrons. The main physics topics of the experiment are:

  • hadron spectroscopy, in particular the search for exotic states build out of charm quarks (so called charmonia) and searches for particles consisting of gluons alone (so called “glueballs”),

  • investigation of properties of mesons embedded in nuclear medium,

  • spectroscopy of double-hypernuclei and study of the nucleon structure.


The PANDA detector is designed for the complete detection and identification of particles produced in the interaction of the antiproton beam with hydrogen or nuclear targets. To ensure a geometrical acceptance close to 4 in the chosen fixed target arrangement, the detection system consists of two spectrometers: the Target Spectrometer based on a solenoid magnet surrounding the interaction point and the Forward Spectrometer using a large gap dipole magnet for momentum analysis of particles emitted at the most forward angles.


Longitudinal section of the PANDA setup with the Target Spectrometer on the left side, and the Forward Spectrometer starting with the dipole magnet on the right. The antiproton beam enters from the left.


Members of the PANDA collaboration from the Cluster of Nuclear Physics Departments are responsible for the construction of planar straw tube detectors for the PANDA Forward Spectrometer. The construction is financed by the Polish Ministry of Science and Higher Education from in-kind contribution to FAIR. The detectors have to register trajectories of charged particles with a high spatial resolution of 0.1 mm at very high rates up to 50 million/sec. The ongoing work also includes preparation of the detector readout electronics as well as development of online data selection and analysis algorithms, e.g. the track finding algorithm, running on heterogeneous computing platforms.


Prototype double layer of straw tube detectors for the PANDA Forward Spectrometer built in the Department of Hadron Physics IF UJ.


The physics program of PANDA and the design of the straw tube detectors are presented in the following two publications:


Contact: prof. dr hab. Jerzy Smyrski