Aumann T, Bertulani C A, Schindler F, Typel S
Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstraße 9, D-64289 Darmstadt, Germany.
GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, D-64291 Darmstadt, Germany.
Phys Rev Lett. 2017 Dec 29;119(26):262501. doi: 10.1103/PhysRevLett.119.262501. Epub 2017 Dec 28.
An experimentally constrained equation of state of neutron-rich matter is fundamental for the physics of nuclei and the astrophysics of neutron stars, mergers, core-collapse supernova explosions, and the synthesis of heavy elements. To this end, we investigate the potential of constraining the density dependence of the symmetry energy close to saturation density through measurements of neutron-removal cross sections in high-energy nuclear collisions of 0.4 to 1 GeV/nucleon. We show that the sensitivity of the total neutron-removal cross section is high enough so that the required accuracy can be reached experimentally with the recent developments of new detection techniques. We quantify two crucial points to minimize the model dependence of the approach and to reach the required accuracy: the contribution to the cross section from inelastic scattering has to be measured separately in order to allow a direct comparison of experimental cross sections to theoretical cross sections based on density functional theory and eikonal theory. The accuracy of the reaction model should be investigated and quantified by the energy and target dependence of various nucleon-removal cross sections. Our calculations explore the dependence of neutron-removal cross sections on the neutron skin of medium-heavy neutron-rich nuclei, and we demonstrate that the slope parameter L of the symmetry energy could be constrained down to ±10 MeV by such a measurement, with a 2% accuracy of the measured and calculated cross sections.
富含中子物质的实验约束状态方程对于原子核物理学以及中子星、并合、核心坍缩超新星爆发和重元素合成的天体物理学至关重要。为此，我们研究了通过测量0.4至1 GeV/核子的高能核碰撞中的中子移除截面来约束接近饱和密度时对称能密度依赖性的潜力。我们表明，总中子移除截面的灵敏度足够高，以至于利用新探测技术的最新进展可以在实验上达到所需的精度。我们量化了两个关键点，以最小化该方法对模型的依赖性并达到所需的精度：必须分别测量非弹性散射对截面的贡献，以便能够将实验截面与基于密度泛函理论和程函理论的理论截面进行直接比较。反应模型的精度应该通过各种核子移除截面的能量和靶标依赖性来研究和量化。我们的计算探索了中子移除截面与中等质量富含中子核的中子皮的依赖性，并且我们证明通过这样的测量，对称能的斜率参数L可以被约束到±10 MeV，测量和计算截面的精度为2%。
