Abstract
We studied simultaneously the , , and reactions at and , for an missing-momentum range of 400 to . The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon () force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond . The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in and discussed in the context of probing the elusive repulsive component of the force.
- Received 13 February 2014
DOI:https://doi.org/10.1103/PhysRevLett.113.022501
© 2014 American Physical Society