The $^{18}F(p,$\alpha$) $^{15}O$ low-energy S--factor: A microscopic approach

M. Dufour (1) , P. Descouvemont (2)

1 DRS-IPHC - Département Recherches Subatomiques
2 Physique Nucléaire Théorique et Physique Mathématique

The $^{18}F(p,$\alpha$) $^{15}$O S--factor is determined in a microscopic cluster model. The wave functions are defined in the Generator Coordinate Method, involving various $^{18}$F + p, $^{15}O+$\alpha$, and $^{18}$Ne + n configurations. We analyze the $^{19}$Ne level scheme, and test the model with the $^{19}$F spectrum, better known experimentally. We focus on 1/2^+ and 3/2^+ states, corresponding to s waves, and expected to represent the main contribution in the $^{18}$F(p,$\alpha$) $^{15}$O cross section at stellar energies. The 1/2^+ partial wave is shown to play an important role in a wide energy range. This property reduces the uncertainties associated with interference patterns in the 3/2^+ contribution. The relevant 1/2^+ states have been observed in $^{19}$F, but have not been searched for in $^{19}Ne. An elastic--scattering experiment above 1 MeV is suggested.

Domaines: Physique Nucléaire Théorique [nucl-th]

M. Dufour, P. Descouvemont. The $^{18}F(p,$\alpha$) $^{15}O$ low-energy S--factor: A microscopic approach. Nuclear Physics A, 2007, 785, pp.381-394. ⟨10.1016/j.nuclphysa.2006.12.101⟩. ⟨in2p3-00142364⟩