First inverse kinematics measurement of resonances in ${}^7$Be($\hat{I}\pm ,{\hat{I}}^3$)${}^{11}$C relevant to neutrino-driven wind nucleosynthesis using DRAGON

Abstract

A possible mechanism to explain the origin of the light $p$-nuclei in the Galaxy is the nucleosynthesis in the proton-rich neutrino-driven wind ejecta of core-collapse supernovae via the $\hat{I}½p$-process. However this production scenario is very sensitive to the underlying supernova dynamics and the nuclear physics input. As far as the nuclear uncertainties are concerned, the breakout from the $pp$-chains via the ${}^7$Be($\hat{I}\pm ,{\hat{I}}^3$)${}^{11}$C reaction has been identified as an important link which can influence the nuclear flow and therefore the efficiency of the $\hat{I}½p$-process. However its reaction rate is poorly known over the relevant temperature range, T = 1.5-3 GK. We report on the first direct measurement of two resonances of the ${}^7$Be($\hat{I}\pm ,{\hat{I}}^3$)${}^{11}$C reaction with previously unknown strengths using an intense radioactive ${}^7$Be beam from the ISAC facility and the DRAGON recoil separator in inverse kinematics. We have decreased the ${}^7$Be($\hat{I}\pm ,{\hat{I}}^3$)${}^{11}$C reaction rate uncertainty to $\sim$ 9.4-10.7% over the relevant temperature region.

15 pages, 12 figures. Accepted for publication in Phys. Rev. C