R. Crespo

Uncertainties in extracting S 17 from transfer reactions

The transfer reaction 7 Be(d,n) 8 B is modelled for the recent low experimental energies using the DWBA. Tests of the validity of the ANC method for the extraction of the S17 astrophysical factor are performed. We show that a peripheral assumption is no longer accurate for center of mass energies greater than approximately 15 MeV. In all cases we found that core deformation and/or excitation effects to be small as long as the optical potential for the entrance channel is not strongly surface peaked. Multistep corrections to the DWBA were found to be small. We also emphasize that the lack of knowledge of the optical potentials for the entrance and outgoing channels induces severe uncertainties in the extracted S17 astrophysical factor.

Uncertainties in extracting S(17) from transfers

The transfer reaction 7 Be(d,n) 8 B is modelled for the recent low experimental energies using the DWBA. Tests of the validity of the ANC method for the extraction of the S17 astrophysical factor are performed. We show that a peripheral assumption is no longer accurate for center of mass energies greater than approximately 15 MeV. In all cases we found that core deformation and/or excitation effects to be small as long as the optical potential for the entrance channel is not strongly surface peaked. Multistep corrections to the DWBA were found to be small. We also emphasize that the lack of knowledge of the optical potentials for the entrance and outgoing channels induces severe uncertainties in the extracted S17 astrophysical factor.

Polarization observables in the elastic scattering of protons from 4,6,8He

We have calculated the p-{sup 4,6,8}He elastic scattering differential cross section and polarizations at 297 MeV using the Multiple Scattering expansion of the Optical potential (MSO) reaction scattering framework. The role of the core and valence neutrons contribution to the interaction in the description of the elastic scattering observables is analyzed.