R-Matrix Analysis of 15 N(p,  0 ) 16 O using the program AZURE. P.J. LeBlanc April 23 rd, 2008 Sante Fe, NM

Outline:  Previous experimental data  Experimental update of the 15 N(p,  0 ) performed at Notre Dame in April 2007  Using AZURE to analyze the results

Experimental Background:  Previous results published by Rolfs in  This data was re-analyzed using an early version of AZURE by Ed Simpson.  Results indicated that the interference between the resonances was critical in determining S(0).

New Experiment at Notre Dame: 3.5 MV KN VdG accelerator 1 MV JN VdG accelerator

Experimental Set ND:  Used a Ge Clover Detector set up at 45°  Clover was used in Add-Back mode.  Targets used were TiN, enriched in 15 N, around 8 keV thick at 430 keV.

Experimental Results:

AZURE Analysis: Set Up  Need Data files:  (p,  0 ) obviously, but any other data will help constrain the parameters.  (p,p) & (p,  0 ) data sets are also included  Nuclear Physics Environment:  Spins and parities of particles involved  Also energy levels and some initial values for the gamma widths.

Current included Data Sets:  15 N(p,p) 15 N  Hagedorn (1957): 160°, 125°, 90°  Bashkin (1959): 90 °, 160.8°  15 N(p,  0 ) 16 O  Notre Dame 2007 Data  15 N(p,  0 ) 12 C  Schardt (1952): 160°  Redder (1982): 160°  Zyskind (1979): 160°

Nuclear Physics Environment Resonance Transitions: & , 1 - States Particle pair   (ev) (p,p)900 (p,g)12 (p,a0) N+p Gamma decay S=0-, l=1 S=1-, l=0,1,2 Indicates component not included by setting rwa = 0.0. In, general, only the lowest l-value is allowed Elastic scattering 15N+p 1- 15N+p 16O+  Starting parameters from TUNL Indicates component excluded by parity considerations. Alpha decay 1- 15N+p 12C+α 0 S=0+, l=1 S=0-, l=1 S=1-, l=0,1,2 E1 0+ Particle pair  i (ev) (p,p) (p,g)32 (p,a0) MeV State MeV State

Initial AZURE calculation: (p,p)

Initial AZURE Calculation: (p,  0 ) & (p,  0 ):  All calculations look very good using just the literature values of the experimental partial widths.  Note that no target integration or convolution included.  So what does the fit look like?

First try for AZURE fit: (p,p)

First try for AZURE fit: (p,  0 ) & (p,  0 ):  Fits still need a little work…but look promising.     / point:   p,p): 1.66  (p,  0 ):.98  (p,  0 ): 6.27

Closing Remarks: Improving the fit  Look into the (p,p) data  Could be a problem with the scan  Notre Dame (p,p) data available  Adding the (p,  1 ) data would help  Include the recent LUNA (p,  0 ) data

Thanks to Dick!  Little did I know back in 2004 what I was getting myself into!!  But working with the AZURE code under Dick’s guidance taught me more nuclear physics than I could have hoped to learn in any class.