An international group of scientists under the guidance of researchers from Michigan University created a “neutron star” in a subatoman scale, in order to better learn about the mysterious properties of matter in the depths of compact space objects. The results of the experiment reported in the article published in the magazine Physical Review Letters.
To simulate the conditions inside the neutron star, scientists used the cores of tin atoms, which dispersed to two thirds of the light speed using an accelerator in the Japanese center Riken Nishina. The bundle was sent through a thin tin foil to destroy the kernels, which for one billion trillional fraction of seconds existed in the form of a super-proper “soup” from protons and neutrons. Nevertheless, this time is enough to form peonies – particles that are carriers of nuclear forces. Peonies were recorded special detectors built by Physicists of Michigan University.
Physics and properties of neutron stars are described by the status equation, which is currently poorly studied. The problem is that with the extreme density values on the properties of the substance, the symmetry energy is largely begins to influence the ability of atomic nuclei to maintain its stability, and also determines the proportion of protons. The experiment of scientists was aimed at limiting the contribution of the symmetry energy into the equation of the state of the substance on the spectra of charged peonies generated by tin isotopes.
With the increasing density of matter, the energy of symmetry is growing, however, with extreme values, the maximum reaches and begins to fall, which corresponds to a decrease in the share of all components of matter, except neutron. Physics calculated the ratio of the spectra of charged peonies and managed to limit the derivative of the energy of symmetry by density (L) by the range from 42 to 117 megaelectronvolt.
This value l is only a little less than the value obtained as a result of measuring the thickness of the neutron shell of lead-208 isotope. According to the theory of the shell structure, the kernel structure can be considered by analogy with the structure of the electronic shells of the atom, so the nucleons (protons and neutrons) fill their shells, increasing the stability of the kernel. Protons and neutrons make it asymmetrically, which becomes especially noticeable for heavy isotopes, which allows scientists to associate the size of the shells with the energy of symmetry.
In the future, scientists plan to carry out more accurate estimates of the energy of symmetry and its derivatives on the FRIB installation (Facility for Rare Isotope Beams), which will be put into operation in 2022. This will allow you to better understand the physics of the environment inside neutron stars.