E.C. SimpsonC. UgaldeM. HeilP.J. LeBlankR.J. DeBoerH. CostantiniE. Uberseder

R.E. AzumaC.R. BruneJ. GoerresM.M. Wiescher

“ In addition, the authors are indebtedTo Fred C. Barker and (ANU, Canberra) and Erich Vogt (Triumf, Vancouver) for many discussions and their help in the AZURE R-matrix project.”

Differential Cross SectionLane and Thomas, Eqns. 2.7 and 2.8, p. 292

where

Angle Integrated Cross section

24°

33°

38.0

43.9°

48.9

54°

58.9°

63.9°

68.9°

74.0°

75.8°

110.8100.8

90.880.8

125.8120.8

115.8110.8

165.8°150.8

140.8130.8

Measurement of 16O Widths:Determination of 15N+p astrophysical reactions

All reactions and data sets analyzed simultaneously(Including radiative direct capture)

Reactions studied:

12C(α,α0)12C 12C(α,α1)12C 12C(α,p)15N 12C(α,γ)16O 15N(p,p0)15N 15N(p,α0)12C 15N(p,α1)12C 15N(p,γ)16O

Data Sets: (a,a0) (a,a1) (a,p0) (a,g)

Tischausser xMorris et al xFeng et al xMitchel et al xMitchel+Ophel xSchuerman et al x

(p,p0) (p0,a0) (p,a1) (p,g)Hagedorn xHagedorn+Marion xBashkin et al x xRedder et al xBray et al xLeBlank etal x

Alpha Entrance-Channel Reactions

Above proton threshold12C(α,α0)12C

167°136°

104°

71°

165°

6.6 MeV 6.99 MeV

7.4 MeV 7.7 MeV

12c(α,α1)12C

Above proton threshold

40°

90° 120°

12C(α,γ)16O and 12C(α,p0)15N

Above proton threshold

Total Cross section

30° 40°

90° 120°

Proton Entrance-Channel Reactions

Threshold Ex=12.127 MeV

25°

105°

0.888 MeV 1.038 MeV

1.163 MeV 1.238 MeV

82°

159.9°

90°

125°

160°

16O(a,g)20Ne

Graphical representation of the related uncertainty between two of the R-matrix fit parameters for the broad resonance at 2.5 MeV. Here the change in chi2 would be on the z-axis. Since the shape is elliptical this signifies that the two parameters have very little correlation. That is, the alpha and gamma widths for this resonance are good (not redundant) fit parameters.

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HTTP://AZURE.ND.EDU