B-11+ALPHA REACTION-RATES AND PRIMORDIAL NUCLEOSYNTHESIS

Total cross sections and resonance yields have been measured for the B-11(alpha,n)N-14 reaction for E-alpha = 350-2400 keV, and for the C-14(p,n)N-14 reaction for E(p) = 1000-1550 keV, using 4-pi neutron detectors. Differential cross sections for the B-11(a,p)C-14 reaction were measured for E-alpha =600-1820 keV. A strong and narrow (GAMMA = 2.2 eV) new resonance was found at E-alpha = 606 keV, with J-pi = 7/2 - established by (alpha,gamma) and (alpha, p) angular distributions. This resonance dominates the thermonuclear (alpha,n) and (alpha,p) reaction rates for tau approximately 0.5 x 10(9) K. The B-11(alpha,n), (alpha,p), and (alpha,gamma) reaction rates versus temperature are presented and compared with B-11(n,gamma) rates.