Speaker
Dr
Ivano Lombardo
(Università di Napoli Federico II and INFN - Sez. Napoli)
Description
The study of $^{13}$C structure allows to understand the effects of clusterization in light non-self-conjugated nuclei. The possible presence of rotational bands built on molecular states has been suggested in several papers [1,2]. Furthermore, in recent times, some theoretical papers [3,4] predicted the possible existence of states corresponding to the coupling of a valence neutrons to the $^{12}$C Hoyle state.
To shed light on these aspects, we performed a comprehensive $R$-matrix fit of $\alpha+^{9}$Be elastic ($\alpha_0$) and inelastic ($\alpha_1$ and $\alpha_2$) scattering data in the energy range E$\simeq$ 3.5 – 10 MeV at several angles [5]. To carefully determine the partial decay widths of states above the $\alpha$ decay threshold we included in the fit procedure also $^{9}$Be($\alpha,n_0$)$^{12}$C$_{gs}$ and $^{9}$Be($\alpha,n_1$)$^{12}$C$_{4.44}$ cross section data taken from [6,7]. This analysis allows to improve the (poorly known) spectroscopy of excited states in $^{13}$C in the E$_x\simeq$12-17 MeV region [8]. Furthermore, a better knowledge of high-energy resonance parameters (especially for broad states) can improve low-energy extrapolations of the $^{9}$Be($\alpha,n$)$^{12}$C reaction $S$-factor, that plays a key role in the description of $^{12}$C nucleosynthesis during a supernova explosions [7,9]. Preliminary results of these studies will be discussed.
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\noindent [1] M. Milin and W. von Oertzen, Eur. Phys. J. A 14 (2202) 295.\\
\noindent [2] N. Furutachi and M. Kimura, Phys. Rev. C 83 (2011) 021303(R).\\
\noindent [3] T. Yamada and Y. Funaki, Phys. Rev. C 92 (2015) 034326.\\
\noindent [4] Y. Chiba and M. Kimura, J. Phys.: Conf. Ser. 569 (2014) 012047.\\
\noindent [5] I. Lombardo et al., Nucl. Instr. Meth. Phys. Res. B 302 (2013) 19.\\
\noindent [6] L. van der Zwan and K. W. Geiger, Nucl. Phys. A 152 (1970) 481.\\
\noindent [7] R. Kunz et al., Phys. Rev. C 53 (1996) 2486.\\
\noindent [8] M. Freer et al., Phys. Rev. C 84 (2011) 034317.\\
\noindent [9] S.E. Woosley and R.D. Hoffman, Astrophys. J. 395 (1992) 202.\\
Primary author
Dr
Ivano Lombardo
(Università di Napoli Federico II and INFN - Sez. Napoli)
