Following a path down the energy ladders of nuclear reactions, we present a beautiful view and reveal some of their mysteries of nuclei, stars, and the Universe. On the energy scale of 100 MeV/nucleon in heavy ion collisions, we apply the nuclear multifragmentation technique to study the liquid-gas phase transition, isospin fractionation, and isoscaling in excited nuclear systems, and the density dependence of the symmetry energy in the nuclear equation of state that is crucial for understanding neutron stars. By going down to energies by more than two orders of magnitude, i.e., < 1 MeV/nucleon, we can directly measure the cross sections for the nuclear reactions occurring in stellar environments. One of the most sought-after reactions in nuclear astrophysics, carbon fusion, will be discussed as an example. At much lower energy scales, cold neutrons and ultra-cold neutrons (<10^-7 eV) (which may be produced in a so-called superthermal process by downscattering in liquid 4He), have been used to measure the neutron lifetime. The anomalous lifetime results obtained with different approaches led to a new proposal of neutron-mirror neutron (n-n’) oscillations. The new n-n’ oscillation model has profound implications for our understanding of fundamental physics and cosmology. Further experimental tests of the model are proposed and discussed.
Conference (Mar. 24, 2025): Uncover the deep secrets of the universe by descending the energy ladders of nuclear reactions
ACS Seaborg Award Symposium Honoring ManYee (Betty) Tsang
Abstract:
Following a path down the energy ladders of nuclear reactions, we present a beautiful view and reveal some of their mysteries of nuclei, stars, and the Universe. On the energy scale of 100 MeV/nucleon in heavy ion collisions, we apply the nuclear multifragmentation technique to study the liquid-gas phase transition, isospin fractionation, and isoscaling in excited nuclear systems, and the density dependence of the symmetry energy in the nuclear equation of state that is crucial for understanding neutron stars. By going down to energies by more than two orders of magnitude, i.e., < 1 MeV/nucleon, we can directly measure the cross sections for the nuclear reactions occurring in stellar environments. One of the most sought-after reactions in nuclear astrophysics, carbon fusion, will be discussed as an example. At much lower energy scales, cold neutrons and ultra-cold neutrons (<10^-7 eV) (which may be produced in a so-called superthermal process by downscattering in liquid 4He), have been used to measure the neutron lifetime. The anomalous lifetime results obtained with different approaches led to a new proposal of neutron-mirror neutron (n-n’) oscillations. The new n-n’ oscillation model has profound implications for our understanding of fundamental physics and cosmology. Further experimental tests of the model are proposed and discussed.