Facility For Antiproton And Ion Research Research Articles

Momentum dependent mean-fields of (anti)hyperons

We investigate the in-medium properties of hyperons and anti-hyperons in the framework of the Non-Linear Derivative (NLD) model. We focus on the momentum dependence of in-medium strangeness optical potentials. The NLD model is based on the simplicity of the well-established Relativistic Mean-Field (RMF) approximation, but it incorporates an explicit momentum dependence on a field-theoretical level. The extension of the NLD model to the (anti)baryon-octet is formulated in the spirit of SU(6) and G-parity arguments. It is shown that with an appropriate choice of momentum cut-offs the Λ, Σ and Ξ optical potentials are consistent with recent studies of the chiral effective field theory and Lattice-QCD calculations over a wide momentum region. In addition, we present NLD predictions for the in-medium momentum dependence of Λ‾-, Σ‾- and Ξ‾-hyperons. This work is important for future experimental studies such as CBM, PANDA at the Facility for Antiproton and Ion Research (FAIR). It is relevant for nuclear astrophysics too.

Scanning of a Double-Sided Germanium Strip Detector

This work presents the results from the characterization of a Position-Sensitive Planar Germanium (PSPGe) detector. The PSPGe detector is a double-sided orthogonal strip detector consisting of 10x10 electrical segmentation along the horizontal and vertical directions. The characterization was performed using the coincidence setup between the PSPGe detector and the well-characterized scanning system employing the positron annihilation correlation principle. The scanning system consists of a Position Sensitive Detector (PSD) and 22Na positron source. The main objective of this study is to deploy PSPGe detector for future decay experiments at the Facility for Antiproton and Ion Research (FAIR), Germany. The measurements have been performed to find the depth of gamma-ray interaction in the planar segmented detector. The 2-Dimensional image obtained from the PSD has been used to find the depth of gamma-ray interaction in the planar strip detector using pulse shape analysis. In addition, the sensitivity of PSPGe detector has been investigated by calculating the rise-time from pulse shapes for the front and back strips of the detector.

Track Finding for the PANDA Detector Based on Hough Transformations

The PANDA experiment at FAIR (Facility for Antiproton and Ion Research) in Darmstadt is currently under construction. In order to reduce the amount of data collected during operation, it is essential to find as many true tracks as possible and to be able to distinguish them from false tracks. Part of the preparation for the experiment is the development of a fast online track finder. This work presents an online track finding algorithm based on Hough transformations, which is comparable in quality and performance to the currently best offline track finder in PANDA. In contrast to most track finders the algorithm can handle the challenge of extended hits delivered by PANDA’s central Straw Tube Tracker and thus benefit from its precise spatial resolution. Furthermore, optimization methods are presented that improved the ghost ratio as well as the speed of the algorithm by 70 %. Due to further development potential in terms of track finding for secondary particles and speed optimization on GPUs, this algorithm promises to exceed the quality and speed of other track finders developed for PANDA.

Design of the barrel and endcap DIRC detectors for particle identification in PANDA

The PANDA experiment at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt/Germany aims to investigate fundamental questions of hadron physics. PANDA is designed as a fixed-target experiment for an antiproton beam with a momentum range of 1.5 GeV/[Formula: see text] to 15 GeV/[Formula: see text]. In order to obtain an excellent particle identification of pions and kaons, two independent DIRC detectors have been developed for two adjacent spatial regions. The Barrel DIRC covers polar angles from [Formula: see text]–[Formula: see text] and performs [Formula: see text] separation with [Formula: see text] or more for momenta from 0.5 to 3.5 GeV/[Formula: see text]. The novel Endcap Disc DIRC (EDD) detector will cover the forward polar angles between [Formula: see text] and [Formula: see text] and will provide a [Formula: see text] separation from 0.5 GeV/[Formula: see text] up to 4 GeV/[Formula: see text] with a separation power at least [Formula: see text]. The design of the Barrel DIRC is based on the successful BaBar DIRC and the SuperB FDIRC R&D with several improvements to optimize the performance for PANDA. Both PANDA DIRC detectors use synthetic fused silica as material for radiators and light guides and lifetime-enhance Microchannel Plate PMTs (MCP-PMTs) as sensors. The Barrel DIRC uses narrow bars as a radiator, a prism-shaped expansion volume and a complex multi-layer spherical lens as focusing system. The Cherenkov radiator for the EDD is a large, 2 cm thick fused silica plate that is divided into four identical quadrants. A combination of bars and cylindrical elements with aluminum coating focus the Cherenkov light on the MCP-PMTs with segmented anode plates. The technical design of the two DIRC detectors and the performance of prototypes, tested in a mixed hadron beam at CERN, will be discussed.

MTOF performance during the first main commissioning beam time at mCBM

The future Facility for Anti-proton and Ion Research (FAIR), currently in construction in Darmstadt, Germany, is one of the largest research projects worldwide. The Compressed Baryonic Matter (CBM) experiment is one of the main pillars at FAIR, studying the quantum chromodynamics (QCD) phase diagram at high baryon densities with unprecedented interaction rate in heavy ion collisions up to 10 MHz. This requires new data-driven readout chain, new data analysis methods and high-rate capable detector systems. The task of the CBM Time-of-Flight wall (CBM-TOF) is the charged particle identification. Multi-gap Resistive Plate Chambers (MRPCs) with different rate capabilities will be used at CBM-TOF corresponding regions. To reduce the commissioning time for CBM, a CBM full system test-setup called mini-CBM (mCBM) had been installed and tested with beams at GSI SIS18 facility in March 2019, which was the first main commissioning beam time at mCBM. These tests were not only system tests to make preparations for CBM but also commissioning runs for mCBM which finally aims at measuring Lambda baryon production with high rate up to 10 MHz. High-rate MRPC prototypes equipped with low resistive glass called MRPC2, were selected to be implemented in mTOF modules for mCBM. The first test results of MRPC2 and the mTOF system will be shown.

Design of the Cryogenic Bypass Line for the SIS100 Synchrotron

This paper presents the selected aspects of a superconducting cryogenic bypass line (BPL) design, a part of the international Facility for Antiproton and Ion Research (FAIR) SIS100 cryogenic system, currently under construction in Darmstadt, Germany. Design, manufacturing, and installation of the superconducting cryogenic bypass line is a part of a Polish in-kind contribution to the FAIR project, realized by the Wroclaw University of Science and Technology. The BPL is dedicated to transferring liquid helium and AC electric current between SIS100 arc sections and superconducting quadrupole magnets located in warm straight sections of the synchrotron. A main innovative feature of the cryogenic bypass line is transferring the electric current and liquid helium in one vacuum vessel, while in other similar projects, namely, the Large Hadron Collider at CERN (CH) or the Tevatron at FermiLab (USA), those functions are separated. The coexistence of superconducting busbars and liquid helium process pipes in one limited space, as well as numerous additional functional and technical requirements, was a source of the serious design and production challenges described in the paper, including two designs of the internal suspension system based on steel rods and aramid cables.

Status of the FAIR facility in Darmstadt

The Facility for Antiproton and Ion Research (FAIR) is currently being built in Darmstadt, Germany. The SIS100 accelerator is at the heart of FAIR and will provide proton and heavy-ion beams for a variety of experiments. There are four main research pillars at FAIR specialized in the field of nuclear, hadron and elementary particle physics, atomic and antimatter physics, high density plasma physics, as well as applications in condensed matter physics, biology and the biomedical sciences. In these proceedings I briefly review the main research pillars of FAIR and the status of its realization.

Preface

FAIRNESS 2019 was the sixth edition in a series of workshops designed to bring together excellent international young scientists with research interests focused on physics at FAIR (Facility for Antiproton and Ion Research) and was held on May 20-24 2019 in Arenzano, Italy. The topics of the workshops cover a wide range of aspects in both theoretical developments and current experimental status, concentrated around the four scientific pillars of FAIR. FAIR is a new accelerator complex with brand new experimental facilities, that is currently being built next to the existing GSI facility close to Darmstadt, Germany.The spirit of the conference is to bring together young scientists, e.g. young non-tenured scientists, postdocs and advanced PhD students to present their work, to foster active informal discussions and build up networks. Every participant in the meeting with the exception of the organizers gives an oral presentation, and all sessions are followed by a long discussion period. During the talks, questions are anonymously collected in a box to stimulate discussions. The broad physics program at FAIR is reflected in the wide range of topics covered by the workshop:□ Atomic and plasma physics, biophysics, material sciences and applications□ Nuclear structure, astrophysics and reactions□ Physics of hot and dense nuclear matter, QCD phase transitions and critical point□ Hadron Spectroscopy, Hadrons in matter and Hypernuclei□ Experimental programs APPA, CBM, HADES, PANDA, NUSTAR, as well as BES, NICA and the RHIC beam energy scanFor these different areas one invited speaker was selected to give a longer introductory presentation. The write-ups of the talks presented at FAIRNESS 2019 are the content of this issue of Journal of Physics: Conference Series and have been refereed according to the IOP standard for peer review. This issue constitutes therefore a collection of the forefront of research that is dedicated to the physics at FAIR.June 2019,Organizers of FAIRNESS 2019: Tetyana Galatyuk, Andreas Bauswein, Marco Destefanis, Claudia Ratti, and Laura Tolos.Support for holding the conference was provided by:

The FAIR Phase 0 program of the CBM TOF

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/cm2. 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 STAR experiment at RHIC and the mini-TOF (mTOF) wall of the mini-CBM (mCBM) experiment at Schwerionensynchrotron18 (SIS18). At STAR, the fixed-target program of the Beam Energy Scan II (BES-II) will rely on 108 CBM MRPC detectors for forward PID at trigger rates of up to 2 kHz. At mCBM, high-performance benchmark runs of Lambda-baryon production at top SIS18 energies and CBM design interaction rates of 10 MHz will become feasible with a PID backbone consisting of 25 CBM MRPC detectors. Apart from the physics perspective, these pre-FAIR involvements will help gathering experience in operating the final CBM TOF wall comprising about 1500 MRPC detectors and 110,000 readout channels. The status of the FAIR phase 0 program will be discussed.

Elliptic flow splitting between protons and antiprotons from hadronic potentials

The difference in elliptic flow between protons and antiprotons, produced in [Formula: see text] collisions at center-of-mass energies [Formula: see text], is studied within a modified version of the ultra-relativistic quantum molecular dynamics (UrQMD) model. Two different model scenarios are compared: the cascade mode and the mean field mode which includes potential interactions for both formed and pre-formed hadrons. The model results for the elliptic flow of protons and the relative elliptic flow difference between protons and antiprotons obtained from the mean field mode agree with the available experimental data, while the elliptic flow difference is near zero for the cascade mode. Our results show that the elliptic flow splitting, observed for particles and antiparticles, can be explained by the inclusion of proper hadronic interactions. In addition, the difference in elliptic flow between protons and antiprotons depends on the centrality and the rapidity window. With smaller centrality and/or rapidity acceptance, the observed elliptic flow splitting is more sensitive to the beam energy, indicating a strong net baryon density dependence of the effect. We propose to confirm this splitting at the upcoming experiments from Beam Energy Scan (BES) Phase-II at Relativistic Heavy Ion Collider (RHIC), the Compressed Baryonic Matter (CBM) at Facility for Antiproton and Ion Research (FAIR), High Intensity heavy ion Accelerator Facility (HIAF) and Nuclotron-based Ion Collider fAcility (NICA).

Time imaging reconstruction for the PANDA Barrel DIRC

The innovative Barrel DIRC (Detection of Internally Reflected Cherenkov light) counter will provide hadronic particle identification (PID) in the central region of the PANDA experiment at the new Facility for Antiproton and Ion Research (FAIR), Darmstadt, Germany. This detector is designed to separate charged pions and kaons with at least 3 standard deviations for momenta up to 3.5 GeV/c, covering the polar angle range of 22̂−140̂. An array of microchannel plate photomultiplier tubes is used to detect the location and arrival time of the Cherenkov photons with a position resolution of 2 mm and time precision of about 100 ps. The time imaging reconstruction has been developed to make optimum use of the observables and to determine the performance of the detector. This reconstruction algorithm performs particle identification by directly calculating the maximum likelihoods using probability density functions based on detected photon propagation time in each pixel, determined directly from the data, or analytically, or from detailed simulations.

PANDA as midrapidity detector for a future HESR Collider at FAIR

Exciting new scientific opportunities are presented for the PANDA detector at the High Energy Storage Ring in the redefined overline{text {p}} text {p}(A) collider mode, HESR-C, at the Facility for Antiproton and Ion Research (FAIR) in Europe. The high luminosity, L sim 10^{31} cm^{-2} s^{-1}, and a wide range of intermediate and high energies, sqrt{s_{text {NN}}} up to 30 GeV for overline{text {p}} text {p}(A) collisions will allow to explore a wide range of exciting topics in QCD, including the study of the production of excited open charm and bottom states, nuclear bound states containing heavy (anti)quarks, the interplay of hard and soft physics in the dilepton production, probing short-range correlations in nuclei, and the exploration of the early, complete overline{text {p}}-p- annihilation phase, where an initially pure Yang–Mills gluon plasma is formed.

Electro-thermal analysis of the superconducting dipole circuit of SIS100

The heavy ion synchrotron SIS100, the core machine of the new international Facility for Antiproton and Ion Research (FAIR) in Darmstadt, is currently under construction. The 108 superconducting dipole magnets of SIS100 will be powered in series with a cycling rate up to 30kAs−1 which corresponds to 4Ts−1. The dipole magnet protection system considers 12 energy extraction resistors and two crowbars at the outputs of two power converters. As a part of the Failure Mode and Effects Analysis, the most critical failures of the magnet protection system are simulated. In this contribution, initial studies of the electrical and thermal behaviour of the SIS100 main dipole circuit during a quench are presented. The dipole magnet design and topology of the powering circuit (including the protection system) are described. The electro-thermal model in use is detailed. Finally, simulation of a failure mode of the magnet protection system is presented and results are discussed.

High-energy-density-science capabilities at the Facility for Antiproton and Ion Research

The Facility for Antiproton and Ion Research (FAIR) will employ the World's highest intensity relativistic beams of heavy nuclei to uniquely create and investigate macroscopic (millimeter-sized) quantities of highly energetic and dense states of matter. Four principal themes of research have been identified: properties of materials driven to extreme conditions of pressure and temperature, shocked matter and material equation of state, basic properties of strongly coupled plasma and warm dense matter, and nuclear photonics with a focus on the excitation of nuclear processes in plasmas, laser-driven particle acceleration, and neutron production. The research program, principally driven by an international collaboration of scientists, called the HED@FAIR collaboration, will evolve over the next decade as the FAIR project completes and experimental capabilities develop. The first programmatic research element, called “FAIR Phase 0, officially began in 2018 to test components, detectors, and experimental techniques. Phase-0 research employs the existing and enhanced infrastructure of the GSI Helmholtzzentrum für Schwerionenforschung (GSI) heavy-ion synchrotron coupled with the PHELIX high-energy, high-intensity laser. The “FAIR Day one” experimental program, presently scheduled to begin in 2025, commences the use of FAIR's heavy-ion synchrotron, coupled to new experimental and diagnostic infrastructure, to realize the envisaged high-energy-density-science research program.

Stimulated Recovery of the Radiation Damage in Lead Tungstate Crystals

The lead tungstate crystal (PbWO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , PWO) is one of the widely used scintillation materials for electromagnetic calorimeters (EMCs) in high-energy physics experiments. The degradation of the optical transmittance in the range of the luminescence spectrum under ionizing radiation leads to losses of the light output resulting in the deterioration of the energy resolution and limiting the lifetime of the calorimeter. A possible way to restore radiation damage is the in situ illumination by visible or near-infrared light of the whole crystal volume. It allows recovering the transmittance losses due to the depopulation of the color centers. Such a kind of stimulated recovery subsystem based on a blue light-emitting diode is considered for the EMC of the PANDA detector at Facility for Antiproton and Ion Research (FAIR) (Darmstadt, Germany). Here, we report on the stimulated recovery studies of the lead tungstate radiation damage induced by external light from laser diodes at different wavelengths. The level of technological development of laser diodes allows increasing the efficiency of the stimulated recovery.

A Flexible Search Coil Set-Up for Magnetic Measurements of Accelerator Dipole Magnets

Search coils are used for fast and reliable measurements of field integrals as well as integral homogeneities of dipole magnets. A long experience exists at GSI Helmholtzzentrum fur Schwerionenforschung (GSI) using search coils in series measurements of synchrotron dipoles as well as measurements of dipoles with large deflecting angles. The biggest advantage of this technique is a direct and fast measurement of the field integral. Current technology, however, always required a dedicated coil for each bending radius and length. A prominent example is High Energy Beam Transfer (HEBT) of the Facility for Antiproton and Ion Research (FAIR) project with 6 different radii between 4.5 m and 167 m. In addition to the 6 coils, radius dependent moving and guiding systems are necessary. To overcome the above mentioned drawbacks we developed a modular search coil system with adjustable radius including the support and movement system. The features of the system and measurement results are presented.

Studies of equation of state properties of high-energy-density matter generated by intense ion beams at the facility for antiprotons and ion research.

The work presented in this paper shows with the help of two-dimensional hydrodynamic simulations that intense heavy-ion beams are a very efficient tool to induce high energy density (HED) states in solid matter. These simulations have been carried out using a computer code BIG2 that is based on a Godunov-type numerical algorithm. This code includes ion beam energy deposition using the cold stopping model, which is a valid approximation for the temperature range accessed in these simulations. Different phases of matter achieved due to the beam heating are treated using a semiempirical equation-of-state (EOS) model. To take care of the solid material properties, the Prandl-Reuss model is used. The high specific power deposited by the projectile particles in the target leads to phase transitions on a timescale of the order of tens of nanosecond, which means that the sample material achieves thermodynamic equilibrium during the heating process. In these calculations we use Pb as the sample material that is irradiated by an intense uranium beam. The beam parameters including particle energy, focal spot size, bunch length, and bunch intensity are considered to be the same as the design parameters of the ion beam to be generated by the SIS100 heavy-ion synchrotron at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt. The purpose of this work is to propose experiments to measure the EOS properties of HED matter including studies of the processes of phase transitions at the FAIR facility. Our simulations have shown that depending on the specific energy deposition, solid lead will undergo phase transitions leading to an expanded hot liquid state, two-phase liquid-gas state, or the critical parameter regime. In a similar manner, other materials can be studied in such experiments, which will be a very useful addition to the knowledge in this important field of research.

Status of the Compressed Baryonic Matter experiment at FAIR

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 diagnostic probes multi-differentially with unprecedented precision, the CBM detector and data acquisition systems are designed to run at reaction rates up to 10 MHz. This requires the development of fast and radiation hard detectors and readout electronics for track reconstruction, electron and muon identification, time-of-flight (TOF) determination and event characterization. The data are read-out by ultra-fast, radiation-tolerant, and free-streaming front-end electronics, and then transferred via radiation-hard data aggregation units and high-speed optical connections to a high-performance computing center. A fast and highly parallelized software will perform online track reconstruction, particle identification and event analysis. The components of the CBM experimental setup will be discussed and results of physics performance studies will be presented.

Simultaneous muon and reference hadron measurements in the compressed baryonic matter experiment at FAIR

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, both electrons and muons will be measured with the same acceptance. Up to now, no di-muon measurements have been performed in heavy-ion collisions at beam energies below 158 A GeV. The main device for electron identification, a Ring Imaging Cherenkov (RICH) detector, can be replaced by a setup comprising hadron absorbers and tracking detectors for muon measurements. In order to obtain a complete picture of the reaction, it is important to measure simultaneously leptons and hadrons. This requirement is fulfilled for the RICH, which has a low material budget, and only little affects the trajectories of hadrons on their way to the Time-of-Flight (TOF) detector. In contrast, the simultaneous measurement of muons and hadrons within the same experimental acceptance poses a substantial challenge. This article reviews the simulated performance of the CBM experiment for muon identification, together with the possibility of simultaneous hadron measurements.

Electromagnetic form factors of the transition from the spin-3/2 Σ to the Λ hyperon

The three electromagnetic form factors for the transition from a $3/{2}^{+}\phantom{\rule{4pt}{0ex}}{\mathrm{\ensuremath{\Sigma}}}^{*}$ hyperon to the ground-state $\mathrm{\ensuremath{\Lambda}}$ hyperon are studied. At low energies, combinations of the transition form factors can be deduced from Dalitz decays of the ${\mathrm{\ensuremath{\Sigma}}}^{*}$ hyperon to $\mathrm{\ensuremath{\Lambda}}$ plus an electron-positron pair. It is pointed out how more information can be obtained with the help of the self-analyzing weak decay of the $\mathrm{\ensuremath{\Lambda}}$. In particular, it is shown that these transition form factors are complex quantities already in this kinematical region. Such measurements are feasible at hyperon factories such as, for instance, the Facility for Antiproton and Ion Research (FAIR). At higher energies, the transition form factors can be measured in electron-positron collisions. The transition form factors are related to decay distributions and differential cross sections. Using dispersion theory, the low-energy electromagnetic form factors for the ${\mathrm{\ensuremath{\Sigma}}}^{*}$-to-$\mathrm{\ensuremath{\Lambda}}$ transition are related to the pion vector form factor. The additionally required input, i.e., the two-pion--${\mathrm{\ensuremath{\Sigma}}}^{*}$--$\mathrm{\ensuremath{\Lambda}}$ amplitudes, is determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory, including the baryons from the octet and the decuplet. A poorly known NLO parameter is fixed to the experimental value of the ${\mathrm{\ensuremath{\Sigma}}}^{*}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}\ensuremath{\gamma}$ decay width. Pion rescattering is taken into account by using dispersion theory and solving a Muskhelishvili-Omn\`es equation. Subtracted and unsubtracted dispersion relations are discussed. However, in view of the fact that the transition form factors are complex quantities, the current data situation does not allow for a full determination of the subtraction constants. To reduce the number of free parameters, unsubtracted dispersion relations are used to make predictions for the transition form factors in the low-energy space- and timelike regions.