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Reanalyses for $^{42-51}$Ca scattering on a $^{12}$C target at $280$ MeV/nucleon based on chiral $g$ folding mode with Gogny-D1S Hartree-Fock-Bogoliubov densities

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 نشر من قبل Masanobu Yahiro Prof.
 تاريخ النشر 2020
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In our previous paper, we predicted $r_{rm skin}$, $r_{rm p}$, $r_{rm n}$, $r_{rm m}$ for $^{40-60,62,64}$Ca after determining the neutron dripline, using the Gogny-D1S HFB (GHFB) with and without the angular momentum projection (AMP). Using the chiral $g$-matrix folding model, we predicted $sigma_{rm R}$ for Ca scattering on a $^{12}$C target at 280 MeV/nucleon, since Tanaka {it el al.} measured interaction cross sections $sigma_{rm I} (approx sigma_{rm R})$ for $^{42-51}$Ca in RIKEN. After our prediction, they determine $r_{rm m}({rm RIKEN})$, $r_{rm skin}({rm RIKEN})$, $r_{rm n}({rm RIKEN})$. In this paper, we reanalyses the $sigma_{rm I}$, since they assumed the Wood-Saxon densities for $^{42-51}$Ca. The $sigma_{rm R}$ calculated with the folding model with GHFB and GHFB+AMP densities almost reproduce the $sigma_{rm I}$. We then scale proton and neutron densities so that $r_{rm p}$ and $r_{rm n}$ may agree with the central values of $r_{rm p}(rm exp)$ and $r_{rm n}({rm RIKEN})$, respectively. The $sigma_{rm R}$ calculated with the scaled densities do not reproduce the central values of $sigma_{rm I}$ perfectly. We then determine the $r_{rm m}$ that agree with the central values of $sigma_{rm I}$, using the chiral $g$-matrix folding model. The fitted $r_{rm m}$ do not reproduce the central values of $r_{rm m}({rm RIKEN})$ perfectly, but are in one $sigma$ level. Finally, we show the $r_{rm skin}$, $r_{rm n}$ determined from the fitted $r_{rm m}$ are close to the original ones except for $r_{rm skin}^{48}$. The fitted $r_{rm skin}^{48}$ is 0.105 fm, while the central value of $r_{rm m}^{48}({rm RIKEN})$ is 0.146 fm. When we fit $r_{rm m}$ to the upper bound of $sigma_{rm I}$, the fitted $r_{rm skin}^{48}$ is 0.164~fm and near the central vale 0.17 fm of the high-resolution $E1$ polarizability experiment.



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We first predict the ground-state properties of Ca isotopes, using the Gogny-D1S Hartree-Fock-Bogoliubov (GHFB) with and without the angular momentum projection (AMP). We find that $^{64}$Ca is an even-dripline nucleus and $^{59}$Ca is an odd-driplin e nucleus, using $A$ dependence of the one-neutron separation energy $S_{1}$ and the two-neutron separation energy, $S_{2}$. As for $S_{1}$, $S_{2}$ and the binding energies $E_{rm B}$, our results agree with the experimental data in $^{40-58}$Ca. As other ground-state properties of $^{40-60,62,64}$Ca, we predict charge, proton, neutron, matter radii, neutron skin and deformation. As for charge radii, our results are consistent with the experimental data in $^{40-52}$Ca. For $^{48}$Ca, our results on proton, neutron, matter radii agree with the experimental data. Very lately, Tanaka et. al. measured interaction cross sections for $^{42-51}$Ca scattering on a $^{12}$C target at an incident energy per nucleon of $E_{rm lab}=280$MeV. Secondly, we predict reaction cross sections $sigma_{rm R}$ for $^{40-60,62,64}$Ca, using a chiral $g$-matrix double-folding model (DFM). To show the reliability of the present DFM for $sigma_{rm R}$, we apply the DFM for the data on $^{12}$C scattering on $^{9}$Be, $^{12}$C, $^{27}$Al targets in $30 < E_{rm lab} < 400 $MeV, and show that the present DFM is good in $30 < E_{rm lab} < 100 $MeV and $250 < E_{rm lab} < 400 $MeV. For $110 < E_{rm lab} < 240 $MeV, our results have small errors. To improve the present DFM for $sigma_{rm R}$, we propose two prescriptions.
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