Speaker
Description
Thirty years ago, the pioneering experiment on $^{44}$Sm($\alpha$,$\gamma$)$^{148}$Gd by Somorjai $et$ $al.$ [1] (discussed first at a workshop in Budapest in 1994) showed that the prediction of astrophysical reaction rates of $\alpha$-induced reactions is very uncertain. The $\alpha$-nucleus potential (AOMP) was realized as the main source of the wide range of predictions. Only a few years ago, it became clear that the wide range of predictions results from the tail of the imaginary part of the AOMP at large radii. This problem was overcome by the construction of the Atomki-V2 AOMP which is based on a folding potential in the real part and a very narrow and sharp-edged imaginary part. The Atomki-V2 AOMP is able to predict the total reaction cross section of $\alpha$-induced cross sections at low energies for intermediate mass and heavy target nuclei with small uncertainties, typically far below a factor of two [2,3]. This was verified by a series of experiments of mainly ($\alpha$,n) type (see also presentation by Gy. Gyürky).
Recently, this work was extended to the study of total reaction cross sections of various projectiles and targets, including tightly bound, weakly bound, and halo-type projectiles. A comparison between the different systems under study can be made using the so-called geometrical reduction scheme, leading to reduced energies $E_{\rm{red}}$ and reduced cross sections $\sigma_{\rm{red}}$. A normalization to a reference calculation with the Atomki-V2 AOMP helped to reveal hitherto unknown details of the $\sigma_{\rm{red}}$ vs. $E_{\rm{red}}$ systematics, in particular towards low energies [4]. This opens the way towards an improved assessment of the energy dependence of the total $^{12}$C + $^{12}$C cross section.
[1] E. Somorjai $et$ $al.$, Astron. Astroph. 333, 1112 (1998)
[2] P. Mohr $et$ $al.$, Phys. Rev. Lett. 124, 252701 (2020)
[3] P. Mohr $et$ $al.$, At. Data Nucl. Data Tables 142, 101453 (2021)
[4] P. Mohr, Europ. Phys. J. A, submitted
| Length of presentation requested | Oral presentation: 17 min + 3 min questions |
|---|---|
| Please select a keyword related to your abstract | Nuclear Theory and Experiments |
