Mon·Mar 13, 2023Monday·March 13, 2023

1. 01*

   Cross section measurement of the 12C(p,gamma)13N reaction with activation in a wide energy range

   Gy. Gyürky🇭🇺 · L. Csedreki🇮🇹 · T. Szücs🇭🇺 · G.G. Kiss🇭🇺 · Z. Halász🇭🇺 · Zs. Fülöp

   The CNO cycle is one of the fundamental processes of hydrogen burning in stars. The first reaction of the cycle is the radiative proton capture on 12C and the rate of this 12C(p,gamma)13N reaction is related to the 12C/13C ratio observed e.g. in the Solar System. The low-energy cross section of this reaction was measured several times in the past, however, the experimental data are scarce in a wide energy range especially around the resonance at 1.7 MeV. In the present work the 12C(p,gamma)13N cross section was measured between 300 and 1900 keV using the activation method. This method was only used several decades ago in the low-energy region. As the activation method provides the total cross section and has uncertainties different from those of the in-beam gamma-spectroscopy technique, the present results provide a largely independent data set for future low-energy extrapolations and thus for astrophysical reaction rate calculations.

   nucl-exastro-ph.SREPJA(2023)·11 citations
2. 02*

   New Constraints on Sodium Production in Globular Clusters From the ${}^{23}$Na${(}^3$He$,\text{d}{)}^{24}$Mg Reaction

   C.Marshall🇺🇸 · K.Setoodehnia🇺🇸 · G.C.Cinquegrana · J.H.Kelly · F.Portillo Chaves · A.Karakas🇦🇺 · R.Longland🇺🇸

   The star to star anticorrelation of sodium and oxygen {is} a defining feature of globular clusters, but, to date, the astrophysical site responsible for this unique chemical signature remains unknown. Sodium enrichment within these clusters depends sensitively on reaction rate of the sodium destroying reactions ${}^{23}$Na$(p,\gamma )$ and ${}^{23}$Na$(p,\alpha )$. In this paper, we report the results of a ${}^{23}$Na${(}^3\text{He},d{)}^{24}$Mg transfer reaction carried out at Triangle Universities Nuclear Laboratory using a $21$ MeV ${}^3$He beam. Astrophysically relevant states {in ${}^{24}$Mg} between $11<E_x<12$ MeV were studied using high resolution magnetic spectroscopy, thereby allowing the extraction of excitation energies and spectroscopic factors. Bayesian methods are combined with the distorted wave Born approximation to assign statistically meaningful uncertainties to the extracted spectroscopic factors. For the first time, these uncertainties are propagated through to the estimation of proton partial widths. Our experimental data are used to calculate the reaction rate. The impact of the new rates are investigated using asymptotic giant branch star models. It is found that while the astrophysical conditions still dominate the total uncertainty, intra-model variations on sodium production from the ${}^{23}$Na$(p,\gamma )$ and ${}^{23}$Na$(p,\alpha )$ reaction channels are a lingering source of uncertainty.

   nucl-exnucl-thPRC(2023)·4 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.