Neutron-proton effective mass splitting in neutron-rich matter at normal   density from analyzing nucleon-nucleus scattering data within an isospin   dependent optical model
  The neutron-proton effective $k$-mass splitting in asymmetric nucleonic matter of isospin asymmetry $\delta$ and normal density is found to be $m^{*}_{n-p}\equiv(m^{*}_{n}-m^{*}_{p})/m=(0.41 \pm0.15)\delta$ from analyzing globally 1088 sets of reaction and angular differential cross sections of proton elastic scattering on 130 targets with beam energies from 0.783 MeV to 200 MeV, and 1161 sets of data of neutron elastic scattering on 104 targets with beam energies from 0.05 MeV to 200 MeV within an isospin dependent non-relativistic optical potential model. It sets a useful reference for testing model predictions on the momentum dependence of the nucleon isovector potential necessary for understanding novel structures and reactions of rare isotopes. 
Xiao-Hua Li, Wen-Jun Guo, Bao-An Li, Lie-Wen Chen, Farrukh J. Fattoyev   and William G. Newton
nucl-th nucl-ex