Astrophysical rate of O-15(alpha,gamma)Ne-19 via the (p, t) reaction in inverse kinematics

A recoil coincidence technique has been applied to measure the alpha-decay branching ratios of near-threshold states in Ne-19. Populating these states using the (p,t) reaction in inverse kinematics, we detected the recoils and their decay products with 100% geometric efficiency using a magnetic spectrometer. Combining our branching ratio measurements with independent determinations of the radiative widths of these states, we calculate the astrophysical rate of O-15(alpha,gamma)Ne-19. Using this reaction rate, we perform hydrodynamic calculations of nova outbursts and conclude that no significant breakout from the hot CNO cycles into the rp process occurs in novae via O-15(alpha,gamma)Ne-19.