Bound Nucleon Structure in Neutron Rich Nuclei*

Atomic nuclei are made of protons and neutrons (nucleons), that are themselves composed of quarks and gluons. New high-energy electron-scattering studies of close-proximity nucleons indicate that their internal quark-gluon structure is different from that of free nucleons. This implies that, in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have its quark structure distorted.  It also suggest the possibility of having fast protons in neutron stars.