Remarkable independence of dynamical polarization potentials of the underlying potential

The dynamical polarization potential (DPP) generated by the coupling of specific reaction channels to the elastic channel can be determined by inverting the elastic channel $S$ matrix from a coupled reaction channel (CRC) calculation. The “bare” potential of the CRC calculation is then subtracted from the inverted potential to yield a local representation of the DPP. Here we study the extent to which the DPP calculated in this way depends upon the bare potential. We find that the DPP caused by coupling to pickup channels, for 30.3 MeV protons scattering from ${}^{40}\mathrm{Ca}$, turns out to be qualitatively and almost quantitatively unaffected by substantial changes in the bare potential. This puts the properties of DPPs established in this way on a firmer foundation.

Figure 1

For 30.3 MeV protons on ${}^{40}\mathrm{Ca}$, the solid lines represent the fit to the elastic scattering angular distribution (top panel) and analyzing power (lower panel) when coupling to the ${\frac{3}{2}}^{+}$ ground state is included in a search on the conventional Wood-Saxon parameters. The dashed lines present the observables with the coupling switched off. The dots represent the experimental data, Ref. [12] for the DCS and Ref. [13] for the AP.

Figure 2

For 30.3 MeV protons on ${}^{40}\mathrm{Ca}$, the solid lines present the DPP caused by coupling to the ${\frac{3}{2}}^{+}$ ground state with the bare potential found by fitting the elastic scattering data. The dashed lines present the DPP calculated with the standard (PRC85) bare potential. The panels present, from the top down, the real central, imaginary central, real spin-orbit, and imaginary spin-orbit components.

Figure 3

Same as Fig. 2, but for the DPP caused by coupling to the ${\frac{5}{2}}^{+}$ lumped state.

Figure 4

For 30.3 MeV protons on ${}^{40}\mathrm{Ca}$, the three bare potentials: dashes represent the PRC85 bare potential, the solid line is for the case with coupling to the ${\frac{3}{2}}^{+}$ ground state, and the dot-dashes represent the bare potential with coupling to the ${\frac{5}{2}}^{+}$ state specified in the text. The panels present, from the top down, the real central, imaginary central, real spin-orbit, and imaginary spin-orbit components.