Nonlocal nucleon-nucleus optical potentials from chiral effective field theory*

We investigate the nonlocality in microscopic optical potentials derived from chiral effective field

theory. For this purpose we employ the Perey-Buck ansatz, which connects the energy dependence of

purely local optical potentials to a Gaussian spatial nonlocality. We find that the dominant source of

energy dependence in the microscopic real optical potential indeed arises from spatial nonlocalities,

while the energy dependence associated with the microscopic imaginary optical potential is a genuine

time nonlocality. We present results for nonlocal nucleon-nucleus optical potentials for the calcium

isotopic chain and study the dependence of the Woods-Saxon shape parameters on the isotopic

number.