Inverse-kinematics proton scattering on $^{50}$Ca: Determining effective   charges using complementary probes
  We have performed measurements of the $0_\mathrm{g.s.}^+ \rightarrow 2_1^+$ excitations in the neutron-rich isotopes $^{48,50}$Ca via inelastic proton scattering on a liquid hydrogen target, using the GRETINA $\gamma$-ray tracking array. A comparison of the present results with those from previous measurements of the lifetimes of the $2_1^+$ states provides us the ratio of the neutron and proton matrix elements for the $0_\mathrm{g.s.}^+ \rightarrow 2_1^+$ transitions. These results allow the determination of the ratio of the proton and neutron effective charges to be used in shell model calculations of neutron-rich isotopes in the vicinity of $^{48}$Ca. 
L. A. Riley, M. L. Agiorgousis, T. R. Baugher, D. Bazin, M. Bowry, P.   D. Cottle, F. G. DeVone, A. Gade, M. T. Glowacki, K....
nucl-ex