A unifying framework for resonance scattering and direct reactions in nuclear astrophysics: a case study of 12C(a,g)16O featuring Kevin Ching Wei Li (University of Oslo)

Hosted by: Araceli García Flores (IFUNAM)

Abstract: Helium burning, governed primarily by the triple-α and 12C(a,g)16O reactions, plays a central role in stellar evolution, supernova progenitors, and the cosmic carbon-to-oxygen ratio. In particular, the remaining uncertainty in the 12C(a,g)16O reaction rate continues to represent one of the most important open problems in nuclear astrophysics. At the same time, the relevant states in 12C and 16O exhibit pronounced clustering, linking astrophysical reaction rates directly to emergent nuclear structure.

In this talk, I will present ongoing efforts toward a unified framework that connects resonant scattering, transfer/direct reactions, and radiative capture within a common formalism. Although resonance scattering and direct reactions provide complementary information on nuclear structure, they are often treated in disconnected ways, while direct reaction analyses can show substantial method dependence and internal inconsistency. The framework builds on R-matrix theory while extending its application to consistently relate information obtained from different experimental methods.

Using the 12C(a,g)16O reaction as a case study, I will discuss how combining both resonant scattering and direct reactions can improve constraints on the astrophysical S-factor for 12C(a,g)16O reaction. More broadly, this approach may help establish more consistent links between reaction observables and underlying nuclear structure across a range of light-ion systems.

Professional Profile: https://www.mn.uio.no/fysikk/english/people/aca/kcli/