Rationale

CaNPAN is the Canadian Nuclear Physics for Astrophysics Network. Since 2021 it creates opportunities for young nuclear astrophysics researchers to straddle the border between nuclear physics experiments and astrophysics nucleosynthesis simulations. CaNPAN's current NSERC-funded project Nuclear Physics of the Dynamic Origin of the elements focuses on developing easy-to-use nuclear astrophysics simulations frameworks in scenarios in which nuclear burning and rapid convective intersect dynamically. These are the environments that requires nuclear physics data for radioactive species, X-ray bursts, nova, shell mergers in massive stars such as C-O shell merges, convective H-He shell interactions that lead to i process or explosive He-shell burning with non-standard progenitor evolutions.

The meeting brings together the CaNPAN collaboration, summarizes the progress over the first years and helps to identify opportunities and priorities for the future.

CaNPAN is member of the international NSF AccelNet IReNA network of networks in nuclear astrophysics. In addition to reviewing CaNPAN science we will dedicate a scientific focus to the nuclear astrophysics of neutron captures on unstable species as they occur in conditions that have higher neutron densities than the classical s process and smaller neutron densities than the r process. We wish to explore this topic with the IReNA and broader nuclear astrophysics community.

This range in neutron density, from about ~10¹²cm^-3 to 10²⁰cm^-3 covers the intermediate (i) process as well as the n process believed to originate in explosive He-shell burning, bridging the gap between i and r process. The i (and n?) processes (in process?) are responsible, for example, for heavy element abundance signatures observed in descendants of the the first generation of stars, such as the C-enhanced metal-poor stars with both Ba and Eu enhancements (CEMP-r/s) and possibly also some of the CEMP-no stars which are probably relics of the very first stars in the universe. Another important observational constraint comes from the measurement of isotopic ratios in pre-solar grains. Measurements of multiple measurements of the same grain are now technically feasible, and initial attempts of interpreting such multi-element isotopic grain measurements indicate substantial challenges to our current understanding.

The goal is to identify scientific opportunities in this emerging area of nuclear physics, combining radioactive beams, neutron science as well as state-of-the-art astrophysical simulations of dynamic nucleosynthesis.

On the experimental side, the i process requires radioactive-beam facilities since the nuclei of interest can be produced in high enough quantities to allow e.g. (d,p) reaction studies to constrain the respective direct neutron capture cross sections. In the past years, several experiments have been carried out in various labs, especially in North America. For example, at the ISAC-II facility at TRIUMF the EMMA recoil mass separator has been coupled to the TIGRESS gamma-array and used for various reaction studies related to heavy element nucleosynthesis, while beta-Oslo measurements have been carried out at Argonne National Laboratory and at the NSCL at Michigan State University. In addition, plans for direct measurements of neutron-induced cross sections of short-lived isotopes in inverse kinematics are actively pursued. Current nuclear physics data is insufficient for the needs of the new generation of astrophysical simulations that strive to shed light on abundances observed, for example in these CEMP stars that carry the signature of the first stars.

The meeting will explore new experimental directions to address the n-capture data needs for unstable species, and identify priorities and opportunities for experiments in the near and more distant future.

Objectives

The object of this workshop is to bring together the CaNPAN members, and to evaluate, assess and plan out next priorities for our project Nuclear Physics for the Dynamic Origin of the Elements (NPDOE). This workshop also aims to connect CaNPAN with the broader IReNA expertise in the specific topic of i- and n-process nucleosynthesis. In this sense the workshop follows up on the The format of the meeting will allow for ample discussion time, yet provide an overview of current and future developments in the field.

Format

Hybrid: The meeting will take place at TRIUMF (Main Office Building). Zoom links will be provided to registered participants.

Please note that while wearing masks is a personal choice, TRIUMF strongly recommends wearing masks in meeting rooms with more than 20 participants (except for the speaker). Visitors will have to provide proof of vaccination at the reception when they arrive.

Financial support

Please contact us if you would be participating from the US as there is IReNA funding availbale to participate in this workshop.

IReNA

IReNA workshops and conferences are community events intended for networking and collaboration as well as learning. We value the participation of every attendee and want all attendees to have an enjoyable and productive experience. Accordingly, all attendees are expected to show respect and courtesy to other attendees throughout the workshop and to abide by the following Code of Conduct. Any participant who wishes to report a violation of this policy is encouraged to speak to Iris Dillmann or Falk Herwig, as they have agreed to serve as a point of contact (or if desired, to another member of the organizing team). Thank you for helping make this a welcoming, friendly event for all.

IReNA Code of Conduct