A new estimate of the Ne-19(p, gamma) Na-20 and O-15(alpha, gamma) Ne-19 reaction rates at stellar energies

New constraints on theF18(p,α)O15Kozub1, Bardayan2, Batchelder3 et al. 2005Phys. Rev. C482430View full textAdd to dashboardCite

“…The coincidence efficiencies are roughly 50%, 60%, and 70%, respectively. Our internal energy calibrations allow identifications of these states which are consistent with known levels in who studied the 19 F(d, n) 20 Ne reaction at several bombarding energies. In Ref.…”

O15(α,γ)Ne19Breakout Reaction and Impact on X-Ray Bursts

“…The result on the lifetime of the 4.03-MeV state was also confirmed in an independent measurement at TRIUMF [21]. The remaining quantity to be determined is the α-decay branching ratios B α = Γ α /Γ that have mostly been estimated from the α strengths of the mirror states in 19 F with large systematic model dependent uncertainties inherent to the DWBA analysis of α-transfer reactions on 15 N [10,14,22]. Several attempts have been made in the past to measure the relative α-decay widths directly [13,17,18,23].…”

“…This suggested that the previous lower limit estimate was too low. Cooper et al on the other hand performed an analytical stability study suggesting that the widely used rate of Langanke et al [10] might be too high [8]. An experimental study of 15 O(α, γ) 19 Ne is clearly necessary.…”

“…While progress has been made, the presently used rates are still relying mainly on theoretical estimates [5,10]. The 15 O(α, γ) 19 Ne reaction rate is expected to be dominated by a single resonance level at an excitation energy of 4.03 MeV in 19 Ne [10] where the resonant rate is defined by N A < σv > res ∝ (kT ) −3/2 (2J + 1)Γ γ Γ α /Γ exp(−E/kT ). Present intensities of radioactive 15 O beams are insufficient for a direct measurement.…”

αcluster structures in unbound states in19Ne

“…The 15 O(α,γ) 19 Ne reaction is known to play a crucial role in the advanced stages of astrophysical hydrogen burning [13]. In the 15 O(α,γ) 19 Ne reaction, the most crucial resonance is known to arise through the J π = 3/2 + resonant level at 504 keV with respect to the α + 15 O threshold (E x = 4.03 MeV).…”