Nucleon momentum gap in asymmetric nuclear matter

Abstract

For more than half a century, nucleons were considered to move continuously in the nuclei. Recent electron-scattering experiments indicate about 20--25% of nucleons in heavier nuclei are involved in the neutron-proton short-range correlations. Nucleons in the nuclei thus have abnormal behavior unlike those in the noninteraction fermi gas. In the neutron-rich nuclei, around the Fermi momentum, the neutron-proton short-range correlations lead to a momentum gap in the proton momentum distribution, which is circumstantially supported by the pionic experimental data. Likewise, there should also be a neutron momentum gap in the proton-rich nuclei. Nucleon momentum gap is thought to have profound and extensive implications in the studies ranging from particle physics to neutron stars as well as ultracold atomic gases.