Abstract
We construct nucleonic microscopic optical potentials by combining the Green's function approach with the coupled-cluster method for Ca40 and Ca48. For the computation of the ground states of Ca40 and Ca48, we use the coupled-cluster method in the singles-and-doubles approximation, while for the A = ±1 nuclei we use particle-attached and particle-removed equation-of-motion method truncated at two-particle-one-hole and one-particle-two-hole excitations, respectively. Our calculations are based on the chiral nucleon-nucleon and three-nucleon interaction NNLOsat, which reproduces the charge radii of Ca40 and Ca48, and the chiral nucleon-nucleon interaction NNLOopt. In all cases considered here, we observe that the overall form of the neutron scattering cross section is reproduced for both interactions, but the imaginary part of the potential, which reflects the loss of flux in the elastic channel, is negligible. The latter points to neglected many-body correlations that would appear beyond the coupled-cluster truncation level considered in this work. We show that, by artificially increasing the parameter η in the Green's function, practical results can be further improved.
| Original language | English |
|---|---|
| Article number | 044625 |
| Journal | Physical Review C |
| Volume | 98 |
| Issue number | 4 |
| DOIs | |
| State | Published - Oct 29 2018 |
Funding
We thank K. Hebeler for providing us with matrix elements in Jacobi coordinates for the interaction at next-to-next-to-leading order. We acknowledge beneficial discussions with Willem Dickhoff, Charlotte Elster, Heiko Hergert, and Gr\u00E9gory Potel. This work was supported by the National Science Foundation under Grant No. PHY-1403906, the Department of Energy under Contract No. DE-FG52-08NA28552, by the Office of Science, U.S. Department of Energy under Award No. DE-SC0013365, and by the Office of Nuclear Physics, U.S. Department of Energy, under Grants No. DE-SC0008499 (SciDAC-3 NUCLEI) and No. DE-SC0018223 (SciDAC-4 NUCLEI) and the Field Work Proposals No. ERKBP57 and No. ERKBP72 at Oak Ridge National Laboratory (ORNL). An award of computer time was provided by the Institute for Cyber-Enabled Research at Michigan State University. Part of this research used resources of the Oak Ridge Leadership Computing Facility located at ORNL, which is supported by the Office of Science of the Department of Energy under Contract No. DE-AC05-00OR22725. This work has been partially supported by U.S. DOE Grant No. DE-FG02-13ER41967. ORNL is managed by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The U.S. Government retains, and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript or allow others to do so for U.S. Government purposes.