New approach to determining radiative capture reaction rates at astrophysical energies

Abstract

Radiative capture reactions play a crucial role in stellar nucleosynthesis but have proved challenging to determine experimentally. In particular, the large uncertainty ($\\sim$100%) in the measured rate of the $^{12}$C$(\\alpha,\\gamma)^{16}$O reaction is the largest source of uncertainty in any stellar evolution model. With development of new high current energy-recovery linear accelerators (ERLs) and high density gas targets, measurement of the $^{16}$O$(e,e^\\prime \\alpha)^{12}$C reaction close to threshold using detailed balance opens up a new approach to determine the $^{12}$C$(\\alpha,\\gamma)^{16}$O reaction rate with significantly increased precision ($<$20%). We present the formalism to relate photo- and electro-disintegration reactions and consider the design of an optimal experiment to deliver increased precision. Once the new ERLs come online, an experiment to validate the new approach we propose should be carried out. This new approach has broad applicability to radiative capture reactions in astrophysics.