Measurement of the 10 keV resonance in the ${}^{10}$B($p,{\alpha }_0$)${}^7$Be reaction via the Trojan Horse Method

The ${}^{10}$B(p,${\alpha }_0$)${}^7$Be bare nucleus astrophysical S(E)-factor has been measured for the first time at energies from about 100 keV down to about 5 keV by means of the Trojan Horse Method (THM). In this energy region, the S(E)-factor is strongly dominated by the 8.699 MeV ${}^{11}$C level (J${}^{\pi }$=$\frac{5}{2}$${}^{+}$), producing an s-wave resonance centered at about 10 keV in the entrance channel. Up to now, only the high energy tail of this resonant has been measured, while the low-energy trend is extrapolated from the available direct data. The THM has been applied to the quasi-free ${}^2$H(${}^{10}$B,${\alpha }_0$${}^7$Be)n reaction induced at a boron-beam energy of 24.5 MeV. An accurate analysis brings to the determination of the ${}^{10}$B(p,${\alpha }_0$)${}^7$Be S(E)-factor and of the corresponding electron screening potential $U_e$, thus giving for the first time an independent evaluation of it.