Coulomb Screening Effect on the Hoyle State Energy in Thermal Plasmas

The first excited J(pi) = 0(+) state of C-12, the so-called Hoyle state, plays an essential role in a triple-alpha (He-4) reaction, which is a main contributor to the synthesis of C-12 in a burning star. We investigate the Coulomb screening effects on the energy shift of the Hoyle state in a thermal plasma environment using precise three-alpha model calculations. The Coulomb screening effect between alpha clusters is taken into account within the Debye-Huckel approximation. To generalize our study, we utilize two standard alpha-cluster models, which treat the Pauli principle between the alpha particles differently. We find that the energy shift does not depend on these models and follows a simple estimation in the zero-size limit of the Hoyle state when the Coulomb screening length is as large as a value typical of such a plasma consisting of electrons and alpha particles.

Automated summary

This study investigates the Coulomb screening effects on the energy shift of the Hoyle state in a thermal plasma environment, which contributes to the synthesis of C-12 in a burning star. The findings show that despite not depending on specific models, the energy shift follows a simple estimation in a plasma consisting of electrons and alpha particles.