Probing high-momentum protons and neutrons in asymmetric nuclei

Without short range interaction, the Pauli exclusion principle causes the majority nucleons (usually neutrons) in an asymmetric nucleus to have higher average momentum than the minority. High-energy electron scattering measurements showed that the short range interaction between the nucleons mainly form correlated high momentum neutron-proton pairs in the nucleus. Thus, in neutron-rich nuclei, protons have greater probability than neutrons to have momentum larger than the Fermi momentum. Based on our new data from CLAS detector at Jefferson Laboratory we claim that this results in protons having higher average momentum than neutrons, i.e., an inversion of the momentum sharing between majority and minority nucleons.