2020/11/19 by K. C. W. Li, Li, K. C. W., F. D. Smit +51
Physics and Astronomy · #Atomic and Molecular Physics #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Physics and Applications #Nuclear physics research studies
paper · pdf · doi:10.48550/arxiv.2011.10112
openalex publication_date 2020/11/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Knowledge of the low-lying monopole strength in \mathrm12C, the Hoyle state in particular, is crucial for our understanding of both the astrophysically important 3α reaction and of α-particle clustering. The \mathrm12C(α, α′)\mathrm12C and \mathrm14C(p, t)\mathrm12C reactions were employed to populate states in 12C. A self-consistent, simultaneous analysis of the inclusive spectra with lineshapes was performed, which accounted for distortion due to nuclear dynamics and experimental effects. Clear evidence was found for excess monopole strength at Ex ∼ 9 MeV, particularly in the \mathrm12C(α, α′)\mathrm12C reaction at 0∘. This additional strength cannot be reproduced by the previously established monopole states between Ex = 7 and 13 MeV. An additional 0+ state at Ex ∼ 9 MeV yielded a significantly improved fit of the data and is the leading candidate for the predicted breathing-mode excitation of the Hoyle state. Alternatively, the results may suggest that a more sophisticated, physically motivated parameterization of the astrophysically important monopole strengths in \mathrm12C is required.