The triple alpha reaction rate and the 2$^+$ resonances in $^{12}$C

TL;DR

This paper calculates the triple alpha reaction rate using a comprehensive three-body approach and compares it with standard methods, highlighting the impact of the $2^+$ resonance energy on astrophysical reaction rates.

Contribution

It presents a full three-body calculation of the triple alpha rate and examines how the unknown $2^+$ resonance energy affects the results.

Findings

Full three-body calculations yield smaller rates than standard models at the same $2^+$ energy.

Rates significantly deviate from previous results for temperatures above 3 GK.

The reaction rate depends strongly on the experimentally uncertain $2^+$ resonance energy.

Abstract

The triple alpha rate is obtained from the three-body bound and continuum states computed in a large box. The results from this genuine full three-body calculation are compared with standard reference rates obtained by two sequential two-body processes. The fairly good agreement relies on two different assumptions about the lowest $2^+$ resonance energy. With the same $2^+$ energy the rates from the full three-body calculation are smaller than those of the standard reference. We discuss the rate dependence on the experimentally unknown $2^+$ energy. Substantial deviations from previous results appear for temperatures above 3 GK.