Chapter 12
Nuclear Matter Properties at High
Densities: Squeezing Out Nuclear Matter
Properties from Experimental Data
Yvonne Leifels
Abstract The nuclear equation of state is a topic of highest current interest in nuclear
physics and astrophysics. The nuclear equation of state governs the evolution of
heavy-ion reactions as well as the characteristics of compact stellar objects like neutron stars, the explosions of supernovae, and the merging of two neutron stars. The
symmetry energy is the part of the equation of state which is connected to the asymmetry in the neutron/proton content. During recent years a multitude of experimental
and theoretical efforts on different fields have been undertaken to constraint its density dependence at low densities but also above saturation density (ρ 0 = 0.16fm
−3 ).
Conventionally, the symmetry energy is described by its magnitude S v and the slope
parameter L, both at saturation density. Values of L ≈ 44–66 MeV and S v ≈ 31–
33 MeV have been deduced in recent compilations of nuclear structure, heavy-ion
reaction, and astrophysics data. Apart from astrophysical data on mass and radii of
neutron stars and the gravitational wave signal of neutron star mergers, heavy-ion
reactions above incident energies of several 100 MeV are the only means to access
the high-density behavior of the symmetry energy. In particular, meson production
and collective flows up to about 1 GeV/nucleon are predicted to be sensitive to the
slope of the symmetry energy as a function of density. From the measurement of
elliptic flow of neutrons with respect to charged particles at GSI, a stringent constraint for the slope of the symmetry energy at supra-saturation densities has been
deduced. Future options to reach even higher densities will be discussed.
Y. Leifels (B)
GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt, Germany
e-mail: y.leifels@gsi.de
© Springer Nature Singapore Pte Ltd. 2021
R. K. Puri et al. (eds.), Advances in Nuclear Physics, Springer Proceedings
in Physics 257, https://doi.org/10.1007/978-981-15-9062-7_12
149
Nuclear Matter Properties at High
Densities: Squeezing Out Nuclear Matter
Properties from Experimental Data
Yvonne Leifels
Abstract The nuclear equation of state is a topic of highest current interest in nuclear
physics and astrophysics. The nuclear equation of state governs the evolution of
heavy-ion reactions as well as the characteristics of compact stellar objects like neutron stars, the explosions of supernovae, and the merging of two neutron stars. The
symmetry energy is the part of the equation of state which is connected to the asymmetry in the neutron/proton content. During recent years a multitude of experimental
and theoretical efforts on different fields have been undertaken to constraint its density dependence at low densities but also above saturation density (ρ 0 = 0.16fm
−3 ).
Conventionally, the symmetry energy is described by its magnitude S v and the slope
parameter L, both at saturation density. Values of L ≈ 44–66 MeV and S v ≈ 31–
33 MeV have been deduced in recent compilations of nuclear structure, heavy-ion
reaction, and astrophysics data. Apart from astrophysical data on mass and radii of
neutron stars and the gravitational wave signal of neutron star mergers, heavy-ion
reactions above incident energies of several 100 MeV are the only means to access
the high-density behavior of the symmetry energy. In particular, meson production
and collective flows up to about 1 GeV/nucleon are predicted to be sensitive to the
slope of the symmetry energy as a function of density. From the measurement of
elliptic flow of neutrons with respect to charged particles at GSI, a stringent constraint for the slope of the symmetry energy at supra-saturation densities has been
deduced. Future options to reach even higher densities will be discussed.
Y. Leifels (B)
GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt, Germany
e-mail: y.leifels@gsi.de
© Springer Nature Singapore Pte Ltd. 2021
R. K. Puri et al. (eds.), Advances in Nuclear Physics, Springer Proceedings
in Physics 257, https://doi.org/10.1007/978-981-15-9062-7_12
149