Quantum three-body calculation of nonresonant triple-α reaction rate at low temperatures

Abstract

Triple‐α reaction rate is re‐evaluated by directly solving the three‐body Schrödinger equation. The resonant and nonresonant processes are treated on the same footing using the continuum‐discretized coupled‐channels method for three‐body scattering. An accurate description of the α‐α nonresonant states significantly quenches the Coulomb barrier between the first two α‐particles and the third α‐particle. Consequently, the α‐α nonresonant continuum states give a markedly larger contribution at low temperatures than that reported in previous studies. We show that Nomoto’s method for three‐body nonresonant capture processes, which is adopted in the NACRE compilation and many other studies, is a crude approximation of the accurate quantum three‐body model calculation. We find an increase in triple‐α reaction rate by 26 orders of magnitude around 107 K compared with the rate of NACRE.