Elasticp+12C scattering between 0.3 and 2 MeV

Abstract

Absolute differential cross-sections of p+ a2C elastic scattering have been measured at 0cm=89.1 ~ 118.7 ~ 146.9 ~ for bombarding energies between 0.3 and 2.0MeV. Revised level parameters of the first three excited states in ~3N have been extracted with a R-matrix analysis. It is shown that the influence of the bound ground-state of ~ 3N has an appreciable effect on low-energy scattering. Recent predictions concerning Mott-Schwinger polarization are also discussed.

AZURE: AnR-matrix code for nuclear astrophysics

“…A separate AZURE fit to the elastic scattering data of Ref. [31] positions the resonance at E p = 1686 keV, in better agreement with previous results [32][33][34]. In light of this discrepancy, and considering the negligible effect of this resonance at astrophysical energies, only the data of Ref.…”

“…Additionally, available elastic scattering data from Ref. [31] were included to further constrain the entrance channel. While the capture data of Ref.…”

“…[29] were fitted simultaneously with the elastic scattering data of Ref. [31]. A renormalization was applied to the capture data to reproduce a peak cross section for the J π = 1/2 + resonance of 102 ± 8 µb recommended in Ref.…”

“…The above-mentioned external capture contributions were also incorporated. Though not observable directly in the capture channel, a subthreshold contribution from the ground state is needed to properly fit the elastic scattering data [31]. Figure 1 shows the nuclear phase shifts calculated from the best fit parameters.…”

“…The uncertainty of the AZURE extrapolation was evaluated by placing a fictitious data point with negligible uncertainty at the energy of interest, varying the magnitude of this data point, and observing the net effect on the χ 2 value of the best fit as a function of the extrapolated 12 C data of [31]. The red (solid) line indicates the best fit with the inclusion of the ground state as a subthreshold component, while the blue (dashed) line is the best fit excluding this contribution.…”