Single neutron transfer on 23Ne and its relevance forthepathway ofnucleosynthesis in astrophysical X-ray bursts

Abstract

We present new experimental measurements of resonance strengths in the astrophysical 23 Al(p, γ) 24 Si reaction, constraining the pathway of nucleosynthesis beyond 22 Mg in X-ray burster scenarios. Specifically, we have performed the first measurement of the (d, p) reaction using a radioactive beam of 23 Ne to explore levels in 24 Ne, the mirror analog of 24 Si. Four strong single-particle states were observed and corresponding neutron spectroscopic factors were extracted with a precision of ∼20%. Using these spectroscopic factors, together with mirror state identifications, we have reduced uncertainties in the strength of the key = 0 resonance at E r = 157 keV, in the astrophysical 23 Al(p, γ) reaction, by a factor of 4. Our results show that the 22 Mg(p, γ) 23 Al(p, γ) pathway dominates over the competing 22 Mg(α, p) reaction in all but the most energetic X-ray burster events (T > 0.85 GK), significantly affecting energy production and the preservation of hydrogen fuel.