Electron scattering on the Hoyle state and carbon production in stars

Abstract

High‐resolution inelastic electron scattering experiments were performed at the S‐DALINAC for a precise determination of the partial pair width Γπ of the second Jπ = 0+ state, the so‐called Hoyle state, in 12C. Results for the monopole matrix element (directly related to Γπ) from a nearly model‐independent analysis based on an extrapolation of low‐q data to zero momentum transfer are presented. Additionally, a Fourier‐Bessel analysis of the transition form factor is discussed. The combined result of both methods leads to a pair width Γπ62.2(10) μeV.