학술논문
Investigation of excited states in $^{18}$Ne via resonant elastic scattering of $^{17}$F+p and its astrophysical implication in the stellar reaction of $^{14}$O($\alpha$,$p$)$^{17}$F
Document Type
Working Paper
Author
Hu, J.; He, J. J.; Xu, S. W.; Chen, Z. Q.; Zhang, X. Y.; Wang, J. S.; Yu, X. Q.; Li, L.; Zhang, L. Y.; Yang, Y. Y.; Ma, P.; Zhang, X. H.; Hu, Z. G.; Guo, Z. Y.; Xu, X.; Yuan, X. H.; Lu, W.; Yu, Y. H.; Zang, Y. D.; Tang, S. W.; Ye, R. P.; Chen, J. D.; Jin, S. L.; Du, C. M.; Wang, S. T.; Ma, J. B.; Liu, L. X.; Bai, Z.; Lei, X. G.; Sun, Z. Y.; Zhang, Y. H.; Zhou, X. H.; Xu, H. S.; Su, J.; Li, E. T.; Wang, H. W.; Tian, W. D.; Li, X. Q.
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Abstract
Properties of proton resonances in $^{18}$Ne have been investigated efficiently by utilizing a technique of proton resonant elastic scattering with a $^{17}$F radioactive ion (RI) beam and a thick proton target. A 4.22~MeV/nucleon $^{17}$F RI beam was produced via a projectile-fragmentation reaction, and subsequently separated by a Radioactive Ion Beam Line in Lanzhou ({\tt RIBLL}). Energy spectra of the recoiled protons were measured by two sets of $\Delta$E-E silicon telescope at center-of-mass scattering angles of $\theta_{c.m.}$$\approx$175${^\circ}$$\pm$5${^\circ}$, $\theta_{c.m.}$$\approx$152${^\circ}$$\pm$8${^\circ}$, respectively. Several proton resonances in $^{18}$Ne were observed, and their resonant parameters have been determined by an $R$-matrix analysis of the differential cross sections in combination with the previous results. The resonant parameters are related to the reaction-rate calculation of the stellar $^{14}$O($\alpha$,$p$)$^{17}$F reaction, which was thought to be the breakout reaction from the hot CNO cycles into the $rp$-process in x-ray bursters. Here, $J^\pi$=(3$^-$, 2$^-$) are tentatively assigned to the 6.15-MeV state which was thought the key 1$^-$ state previously. In addition, a doublet structure at 7.05 MeV are tentatively identified, and its contribution to the resonant reaction rate of $^{14}$O($\alpha$,$p$)$^{17}$F could be enhanced by at least factors of about 4$\sim$6 in comparison with the previous estimation involving only a singlet. The present calculated resonant rates are much larger than those previous values, and it may imply that this breakout reaction could play a crucial role under x-ray bursters conditions.
Comment: 8 figures, 2 tables
Comment: 8 figures, 2 tables