Cluster states and their potential contribution to carbon burning in massive stars

TY - JOUR

T1 - Cluster states and their potential contribution to carbon burning in massive stars

AU - Cseh, J.

AU - Riczu, G.

AU - Jenkins, D. G.

N1 - Publisher Copyright: © 2024 American Physical Society.

PY - 2024/4/4

Y1 - 2024/4/4

N2 - Background: A recent inelastic α-scattering experiment [P. Adsley, Phys. Rev. Lett. 129, 102701 (2022)0031-900710.1103/PhysRevLett.129.102701] found 0+ resonances in Mg24 on and above the C12+C12 break-up threshold. It has been conjectured that the states have a C12+C12 cluster structure, and play a similar role in accelerating C12+C12 fusion to the manner in which the Hoyle state accelerates production of C12 in massive stars. Purpose: We aim to build up a quantitative theoretical basis for the considerations of the Hoyle-state paradigm, by calculating the distribution of the 0+ states in the shell model, as well as in the relevant cluster models. Methods: We determine the spectrum of excited 0+ states in Mg24 nucleus using multiconfigurational dynamical symmetry calculations leading to a unified description of the quartet (or shell), C12+C12 and Ne20+He4 cluster configurations. Results: The density of 0+ states in the quartet spectrum is comparable to that found in experiment; however, the density of cluster states is considerably less. Conclusions: The recently observed α-scattering resonances do not seem to be simple C12+C12 cluster states, but are more plausibly interpreted as fragmented cluster states due to coupling to quartet excitations, as background states.

AB - Background: A recent inelastic α-scattering experiment [P. Adsley, Phys. Rev. Lett. 129, 102701 (2022)0031-900710.1103/PhysRevLett.129.102701] found 0+ resonances in Mg24 on and above the C12+C12 break-up threshold. It has been conjectured that the states have a C12+C12 cluster structure, and play a similar role in accelerating C12+C12 fusion to the manner in which the Hoyle state accelerates production of C12 in massive stars. Purpose: We aim to build up a quantitative theoretical basis for the considerations of the Hoyle-state paradigm, by calculating the distribution of the 0+ states in the shell model, as well as in the relevant cluster models. Methods: We determine the spectrum of excited 0+ states in Mg24 nucleus using multiconfigurational dynamical symmetry calculations leading to a unified description of the quartet (or shell), C12+C12 and Ne20+He4 cluster configurations. Results: The density of 0+ states in the quartet spectrum is comparable to that found in experiment; however, the density of cluster states is considerably less. Conclusions: The recently observed α-scattering resonances do not seem to be simple C12+C12 cluster states, but are more plausibly interpreted as fragmented cluster states due to coupling to quartet excitations, as background states.

UR - http://www.scopus.com/inward/record.url?scp=85189325013&partnerID=8YFLogxK

U2 - 10.1103/PhysRevC.109.044309

DO - 10.1103/PhysRevC.109.044309

M3 - Article

AN - SCOPUS:85189325013

SN - 2469-9985

VL - 109

JO - Physical Review C

JF - Physical Review C

IS - 4

M1 - 044309

ER -