New $\alpha$ ANC measurement of the 1/2${}^{+}$ state in ${}^{17}$O at 6.356 MeV, that dominates the ${}^{13}$C($\alpha$,n)${}^{16}$O reaction rate at temperatures relevant for the s-process

Abstract

Background: Accurate knowledge of the ${}^{13}$C($\alpha$,$n$)${}^{16}$O reaction cross section is important for the understanding of the s-process in AGB stars, since it is considered to be the main source of neutrons. The sub-threshold 1/2${}^{+}$ state at excitation energy of 6.356 MeV in ${}^{17}$O has a strong influence on the reaction cross section at energies relevant for astrophysics. Several experiments have been performed to determine the contribution of this state to the ${}^{13}$C($\alpha ,n{)}^{16}$O reaction rate. Nevertheless, significant discrepancies between different measurements remain. Purpose: The aim of this work is to investigate these discrepancies. Method: An 8 MeV ${}^{13}$C beam (below the Coulomb barrier) was used to study the $\alpha$-transfer reaction ${}^6$Li(${}^{13}$C,$d$)${}^{17}$O. Results: The squared Coulomb modified ANC of the 1/2${}^{+}$ state in ${}^{17}$O measured in this work is $({\tilde{C}}_{\alpha {-}^{13}\text{C}}^{{}^{17}\text{O}(1/2+)}{)}^2=3.6\pm 0.7{\text{fm}}^{-1}$. Conclusions: Discrepancy between the results of $\alpha$-transfer experiments have been resolved. However, some discrepancy with the most recent measurement using the Trojan Horse method remains.

References in corpus (4)

• New determination of the 13C(a, n)16O reaction rate and its influence on the s-process nucleosynthesis in AGB stars
• Constraining the 6.05 MeV 0${}^{+}$ and 6.13 MeV 3${}^{-}$ cascade transitions in the ${}^{12}$C($\alpha$,$\gamma$)${}^{16}$O reaction using the Asymptotic Normalization Coefficients
• DWBA analysis of the 13C(6Li,d)17O reaction at 10 MeV/nucleon and its astrophysical implications
• $\alpha$-cluster ANCs for nuclear astrophysics

Cited by in corpus (14)

• LUNA: Status and Prospects
• Direct measurement of the 13C(α,n)16O cross section into the s-process Gamow peak
• The importance of the 13C(alpha,n)16O reaction in Asymptotic Giant Branch stars
• Concurrent application of ANC and THM to assess the ${}^{13}\mathrm{C}(\alpha ,n{)}^{16}\mathrm{O}$ absolute cross section at astrophysical energies and possible consequences for neutron production in low-mass AGB stars
• Broad levels in ${}^{17}$O and their relevance for the astrophysical s-process
• Deep underground laboratory measurement of ${}^{13}$C($\alpha$,$n$)${}^{16}$O in the Gamow windows of the $s$- and $i$-processes
• Constraining the ${}^{22}$Ne($\alpha$,$\gamma$)${}^{26}$Mg and ${}^{22}$Ne($\alpha$,n)${}^{25}$Mg reaction rates using sub-Coulomb $\alpha$-transfer reactions
• The study of key reactions shaping the post main-sequence evolution of massive stars in underground facilities
• Subthreshold resonances and resonances in the $R$-matrix method for binary reactions and in the Trojan Horse method
• Underground Measurements of Nuclear Reaction Cross-Sections Relevant to AGB Stars
• Trojan horse method as surrogate indirect approach to study resonant reactions in nuclear astrophysics
• A Cautionary Tale: The Coulomb Modified ANC for the $1/2_2^{+}$ State in ${}^{17}$O
• Status and future directions for direct cross-section measurements of the 13C(a,n)16O reaction for astrophysics
• Transfer reactions as a Tool in Nuclear Astrophysics