Screening enhancement factors for laboratory CNO and rp astrophysical reactions

Abstract

Cross sections of laboratory CNO and rp astrophysical reactions are enhanced due to the presence of the multi-electron cloud that surrounds the target nuclei. As a result the relevant astrophysical factors are overestimated unless corrected appropriately. This study gives both an estimate of the error committed if screening effects are not taken into account and a rough profile of the laboratory energy thresholds at which the screening effect appears. The results indicate that, for most practical purposes, screening corrections to past relevant experiments can be disregarded. Regarding future experiments, however, screening corrections to the CNO reactions will certainly be of importance as they are closely related to the solar neutrino fluxes and the rp process. Moreover, according to the present results, screening effects will have to be taken into account particularly by the current and future LUNA experiments, where screened astrophysical factors will be enhanced to a significant degree. PACS number(s): 26.30.+k, 25.60.Dz, 25.60.Pj, 25.70.Gh., 26.65.+t Typeset using REVT E X * www.liolios.info

IMPACT OF A REVISED25Mg(p, γ)26Al REACTION RATE ON THE OPERATION OF THE Mg-Al CYCLE

“…This discrepancy is still far from being solved and certainly deserves further studies. It is worth noting that alternative approaches have been discussed in the literature (Liolios 2001(Liolios , 2003 which lead to slightly different values for the screening potential. In order to account for this ambiguity in the theoretical calculation of the electron screening potential, we assign an uncertainty to the adiabatic limit enhancement factor equal to 30% of the difference between its value and unity.…”