Proton 0.01 MeV resonance width and low-energy $S$-factor of p+10B fusion

Abstract

{\bf{Purpose}:} In this paper, the proton resonance width of the near-threshold resonance is calculated using two different approaches. The values of the proton width are used to calculate the low-energy $S$-factor. \\ {\bf{Method:}} First, the proton resonance width is estimated using the mirror symmetry of the resonance $ {}^{11}{\rm C}(E_{x}=8.70\, {\rm MeV};\,\frac{5}{2}^{+})$ and the mirror bound state ${}^{11}{\rm B}(E_{x}=9.272\, {\rm MeV};\,\frac{5}{2}^{+})$. In the second approach, this width is estimated using the $R$-matrix definition of the observable resonance width, which is expressed in terms of the $p-{}^{10}{\rm B}$ resonant wave function calculated in the potential approach and the spectroscopic factor. \\ {\bf{Results}:} Depending on the method chosen, the calculated proton resonance width varies from $\,1.03 \times 10^{-19}\,$MeV to $\,2.96 \times 10^{-19}\,$MeV. The role of the near-threshold resonance is determined using fitting of two low-energy $S$-factors from direct measurements [C. Angulo {\it et al.}, Z. Phys. A {\bf 345}, 333 (1993)] and from the indirect Trojan horse method (THM) [ A. Cvetinovi\'c {\it et al.}, Phys. Rev. C {\bf 97}, 065801 (2018)]. Within the framework of the $R$-matrix method using the determined proton resonance widths and the modified THM parameters for six low-lying resonances, the low-energy $S$-factors were calculated and compared with the corresponding experimental $S$-factors. The closest agreement with the data is achieved with the proton resonance widths $1.0 \times 10^{-19}$ MeV when fitting the $S$-factor from the THM indirect measurements, and $\,1.68 \times 10^{-19}\,$ MeV and $\,2.5 \times 10^{-19}\,$ MeV when fitting the $S$-factor from [Angulo {\it et al}, Z. Phys. A {\bf 345}, 333 (1993)].\