(α,n) reactions play a pivotal role in a variety of astrophysical sites and mass regions, and they can help us understand the origin of the elements. Their astrophysical rates are the main nuclear physics uncertainty in the weak r-process (also known as the α-process), which occurs in the neutrino driven ejecta of core-collapse supernovae and can explain the production of the lighter heavy elements, that are observed in metal poor stars. The 22Ne(α,n)25Mg and 13C(α,n)16O reactions are the main neutron sources for the s- and the i-processes. In addition, (α,n) reactions on 17< A <34 nuclei could affect nucleosynthesis in Type Ia supernova explosions. As far as the low mass regime is concerned, the 9Be(α,n)12C is a key reaction for the s- and r-processes, as well as for primordial nucleosynthesis.

Under the light of recent advancements in astronomical observations (e.g. more metal poor stars), stellar modelling and nuclear physics experiments, there is an intense interest in (α,n) reactions both from an experimental and a theoretical perspective. With this virtual workshop we aim on bringing experts from the international nuclear astrophysics community together to discuss and set future directions for the study of (α,n) reactions for astrophysics. We hope to provide a setting where the community will meet, exchange ideas and build and strengthen international collaborations. We highly encourage students, postdocs and early career scientists to give talks on their projects related to the workshop topic.

Some interesting questions that we look forward to discussing are: How different experimental techniques can help us constrain the alpha-optical potential? Is there a need for a database of such quantities? Can the stellar modeling provide additional sites where (α,n) reactions play a key role? How could advancements in nuclear reaction theory help us understand these alpha-induced reactions?

This is the description of the first workshop I organized along with my supervisor Almudena Arcones, Alison Laird and Zach Meisel virtually. It was supported by IReNA, which provided all the online resources needed. 🙏 There were 84 participants from 13 countries and all the talks were of very high level. If you want more details, visit the workshop website.

Below I am listing the invited speakers and the workshop sessions:

Invited speakers:

  • Melina Avila (ANL)
  • Fernando Montes (FRIB/MSU)
  • Yong-Zhong Qian (University of Minnesota)
  • Wei Jia Ong (LLNL)
  • Jorge Pereira (NSCL/FRIB)

July 14th

  • 1st session: The weak r-process
  • 2nd session: The 22Ne(α,n)25Mg reaction

July 15th

  • 3rd session: Experimental Techniques
  • 4th session: The 13C(α,n)16O reaction
  • 5th session: Astrophysics and experiments