IMPROVING R-MATRIX ESTIMATES OF ASTROPHYSICAL S-FACTORS

We consider processes, such as the critically important alpha capture by C-12, which involve many nuclear resonance levels and reaction chan nels and also large energy extrapolations to obtain S-factors. The R-m atrix is commonly used to analyze the data and make the extrapolations . We liberate the analysis from significant unreliability by showing t hat, contrary to general belief, the R-matrix has unique matching radi i determined by the physics of the nuclear mean-field. The mean-field also reduces the S-factors slightly.