Chapter 11
Influence of the Neutron Skin of Nuclei
on Observables
Christoph Hartnack, Arnaud Le Févre, Yvonne Leifels, and Jörg Aichelin
Abstract We use the Isospin-dependent Quantum Molecular Dynamics approach
to analyze the influence of the neutron skin on hadronic observables in heavy-ion
collisions at 400 AMeV incident energy. While the most observables on the behavior
of nucleons seem to be only slightly affected, the isospin ratios of pions show a quite
significant effect. It is found that the comparison of the centrality dependence at
different energies allows to gain information on the neutron skin of the nuclei on one
hand, but also on other ingredients like the nuclear equation of state of asymmetric
matter.
11.1 Introduction
One of the main interests of the study of relativistic heavy-ion collisions is the
investigation of the properties of nuclear matter at extreme densities and excitation
energies. These investigations include dynamical observables of nucleons on one side
but also the production of secondary particles on the other side, where the pion is the
“cheapest” in production and thus the most prominent produced particle in heavyion collisions beyond 1 AGeV. For our calculations we use the isospin-dependent
quantum molecular dynamics (IQMD) approach [1], a microscopic transport model
calculating heavy-ion collisions on an event-by-event basis. In the first part we will
concentrate on the production of pions, especially on their isospin ratios, where
recently a strong dependence on the neutron skin has been reported [2]. For this we
will first describe how the production of pions is done in IQMD and how the density
C. Hartnack (B) · J. Aichelin
SUBATECH, UMR 6457, IMT Atlantique, IN2P3/CNRS, Université de Nantes, 4 rue
Alfred Kastler, 44 307 Nantes, France
e-mail: hartnack@subatech.in2p3.fr
A. Le Févre · Y. Leifels
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt,
Germany
J. Aichelin
Frankfurt Institute for Advanced Studies, Ruth Moufang Str. 1, 60438 Frankfurt, Germany
© 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_11
137
Influence of the Neutron Skin of Nuclei
on Observables
Christoph Hartnack, Arnaud Le Févre, Yvonne Leifels, and Jörg Aichelin
Abstract We use the Isospin-dependent Quantum Molecular Dynamics approach
to analyze the influence of the neutron skin on hadronic observables in heavy-ion
collisions at 400 AMeV incident energy. While the most observables on the behavior
of nucleons seem to be only slightly affected, the isospin ratios of pions show a quite
significant effect. It is found that the comparison of the centrality dependence at
different energies allows to gain information on the neutron skin of the nuclei on one
hand, but also on other ingredients like the nuclear equation of state of asymmetric
matter.
11.1 Introduction
One of the main interests of the study of relativistic heavy-ion collisions is the
investigation of the properties of nuclear matter at extreme densities and excitation
energies. These investigations include dynamical observables of nucleons on one side
but also the production of secondary particles on the other side, where the pion is the
“cheapest” in production and thus the most prominent produced particle in heavyion collisions beyond 1 AGeV. For our calculations we use the isospin-dependent
quantum molecular dynamics (IQMD) approach [1], a microscopic transport model
calculating heavy-ion collisions on an event-by-event basis. In the first part we will
concentrate on the production of pions, especially on their isospin ratios, where
recently a strong dependence on the neutron skin has been reported [2]. For this we
will first describe how the production of pions is done in IQMD and how the density
C. Hartnack (B) · J. Aichelin
SUBATECH, UMR 6457, IMT Atlantique, IN2P3/CNRS, Université de Nantes, 4 rue
Alfred Kastler, 44 307 Nantes, France
e-mail: hartnack@subatech.in2p3.fr
A. Le Févre · Y. Leifels
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt,
Germany
J. Aichelin
Frankfurt Institute for Advanced Studies, Ruth Moufang Str. 1, 60438 Frankfurt, Germany
© 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_11
137