Exploring Baryon Rich Matter with Heavy-Ion Collisions

  • S. Harabasz Institut f¨ur Kernphysik, Technische Universit¨at Darmstadt/GSI
Keywords: heavy-ion collisions, HADES, vector meson dominance, dileptons, strangeness

Abstract

Collisions of heavy nuclei at (ultra-)relativistic energies provide a fascinating opportunity to re-create various forms of matter in the laboratory. For a short extent of time (10-22 s), matter under extreme conditions of temperature and density can exist. In dedicated experiments, one explores the microscopic structure of strongly interacting matter and its phase diagram. In heavy-ion reactions at SIS18 collision energies, matter is substantially compressed (2–3 times ground-state density), while moderate temperatures are reached (T < 70 MeV). The conditions closely resemble those that prevail, e.g., in neutron star mergers. Matter under such conditions is currently being studied at the High Acceptance DiElecton Spectrometer (HADES). Important topics of the research program are the mechanisms of strangeness production, the emissivity of matter, and the role of baryonic resonances herein. In this contribution, we will focus on the important experimental results obtained by HADES in Au+Au collisions at 2.4 GeV center-of-mass energy. We will also present perspectives for future experiments with HADES and CBM at SIS100, where higher beam energies and intensities will allow for the studies of the first-order deconfinement phase transition and its critical endpoint.

References

M. Hanauske et al. Neutron star mergers: Probing the EoS of hot, dense matter by gravitational waves. Particles 2, 44 (2019). https://doi.org/10.3390/particles2010004

G. Agakichiev et al. (HADES). The high-acceptance dielectron spectrometer HADES. Eur. Phys. J. A 41, 243 (2009).

G. Ramalho, M.T. Pe?na, J. Weil, H. van Hees, U. Mosel. Role of the pion electromagnetic form factor in the ?(1232) > y*N timelike transition. Phys. Rev. D 93, 033004 (2016). https://doi.org/10.1103/PhysRevD.93.033004

M. Bashkanov, H. Clement. On a Possible Explanation of the DLS Puzzle. Eur. Phys. J. A 50, 107 (2014). https://doi.org/10.1140/epja/i2014-14107-9

G. Ramalho, M.T. Pe?na, J. Weil, H. van Hees, U. Mosel. The high-acceptance dielectron spectrometer HADES. Phys. Rev. D 93, 033004 (2016). https://doi.org/10.1103/PhysRevD.93.033004

R. Shyam, U. Mosel. Dilepton production in proton-proton and quasi-free proton-neutron reactions at 1.25 GeV. Phys. Rev. C 82, 062201 (2010). https://doi.org/10.1103/PhysRevC.82.062201

M. Z?et?enyi, Gy. Wolf. Dilepton decays of baryon resonances. Heavy Ion Phys. 17, 27 (2003). https://doi.org/10.1556/APH.17.2003.1.5

F. Dohrmann et al. A versatile method for simulating pp>pp e+e? and dp>pn e+e? p(spec) reactions. Eur. Phys. J. A 45, 401 (2010). https://doi.org/10.1140/epja/i2010-11012-3

F. Iachello and Q. Wan. Structure of the nucleon from electromagnetic timelike form factors. Phys. Rev. C 69, 055204 (2004). https://doi.org/10.1103/PhysRevC.69.055204

Q. Wan, F. Iachello. A unified description of baryon electromagnetic form factors. Int. J. Mod. Phys. A 20, 1846 (2005). https://doi.org/10.1142/S0217751X05023463

Q. Wan, PhD Thesis. A Unified Approach to Baryon Electromagnetic Form Factors (Yale University, New Haven, (2007).

J. Adamczewski-Musch et al. (HADES Collaboration). ?(1232) Dalitz decay in proton-proton collisions at T = 1.25 GeV measured with HADES at GSI. Phys. Rev. C 95, 065205 (2017).

J. Adamczewski-Musch et al. (HADES Collaboration). entrality determination of Au + Au collisions at 1.23A GeV with HADES. Eur. Phys. J. A 53, 149 (2017).

J. Adamczewski-Musch et al. (HADES Collaboration). Probing dense baryon-rich matter with virtual photons. Nature Physics. https://doi.org/10.1038/s41567-019-0583-8

S. Endres et al.. Dilepton production and reaction dynamics in heavy-ion collisions at SIS energies from coarse-grained transport simulations. Phys. Rev. C 92, 014911 (2015). https://doi.org/10.1103/PhysRevC.92.014911

T. Galatyuk et al. Thermal dileptons from coarse-grained transport as fireball probes at SIS energies. Eur. Phys. J. A 52, 131 (2016). https://doi.org/10.1140/epja/i2016-16131-1

J. Staudenmaier et al. Dilepton production and resonance properties within a new hadronic transport approach in the context of the GSI-HADES experimental data. Phys. Rev. C 98, 054908 (2018). https://doi.org/10.1103/PhysRevC.98.054908

E. L. Bratkovskaya et al. System size and energy dependence of dilepton production in heavy-ion collisions at 1-2 GeV/nucleon energies. Phys. Rev. C 87, 064907 (2013). https://doi.org/10.1103/PhysRevC.87.064907

J. Adamczewski-Musch et al. (HADES Collaboration). Sub-threshold production of Ks0 mesons and ? hyperons in Au+Au collisions at vSNN = 2.4 GeV. Phys. Lett. B 793, 457 (2019).

J. Adamczewski-Musch et al. (HADES Collaboration). Deep sub-threshold ф production in Au+Au collisions. Phys. Lett. B 778, 403 (2018).

S.A. Bass et al. Microscopic models for ultrarelativistic heavy ion collisions. Prog. Part. Nucl. Phys. 41, 225 (1998). https://doi.org/10.1016/S0146-6410(98)00058-1

C. Hartnack. et al. Modeling the many body dynamics of heavy ion collisions: Present status and future perspective. Eur. Phys. J. A 1, 151 (1998). https://doi.org/10.1007/s100500050045

W. Cassing, E.L. Bratkovskaya. Hadronic and electromagnetic probes of hot and dense nuclear matter. Phys. Rept. 308, 65 (1999). https://doi.org/10.1016/S0370-1573(98)00028-3

Published
2019-09-17
How to Cite
Harabasz, S. (2019). Exploring Baryon Rich Matter with Heavy-Ion Collisions. Ukrainian Journal of Physics, 64(7), 583. https://doi.org/10.15407/ujpe64.7.583
Section
New Trends in High-Energy Physics (Conference materials)