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Jakub Skowronski

Running on AZURE2

R-matrix evaluations

A research tool for nuclear physicists, built to be used rather than read. For what these reactions do in stars and how they are measured, the reaction atlas is the place to start.

Each of these is a multi-level, multi-channel R-matrix fit. Open one to see its level scheme and the data it was fitted to, then move a level energy or a width and see the cross section and the χ² change — the calculation is AZURE2 itself, not an approximation. Every evaluation can also be downloaded as an .azr project and run locally.

  • 12C(p,γ)13N

    12C(p,p)12C

    Compound nucleus 13N

    The first step of the CN cycle, which burns hydrogen in stars; with the next proton capture it sets the carbon-12 to carbon-13 ratio seen in red giants. · opens in about 1 s

    Preliminary model; published results: J. Skowronski et al., Phys. Rev. C 111, 035802 (2025)R-matrix analysis: J. Skowronski

  • 13C(p,γ)14N

    13C(p,p)13C

    Compound nucleus 14N

    The step of the CN cycle that destroys carbon-13 and makes nitrogen-14. · opens in about 1 s

    Preliminary model; published results: J. Skowronski et al., Phys. Rev. C 111, 064611 (2025)R-matrix analysis: J. Skowronski

  • 16O(p,γ)17F

    Compound nucleus 17F

    The slowest step of the second CNO cycle. · opens in about 1 s

    Not yet publishedR-matrix analysis: R. J. deBoer

  • 20Ne(p,γ)21Na

    20Ne(p,p)20Ne

    Compound nucleus 21Na

    The first and slowest step of the NeNa cycle. · opens in about 1 s

    E. Masha et al., Phys. Rev. C 108, L052801 (2023)R-matrix analysis: J. Skowronski

  • 22Ne(p,γ)23Na

    Compound nucleus 23Na

    The main way stars make sodium-23, the only stable sodium isotope, while they burn hydrogen. · opens in about 1 s

    M. P. Takács et al., Phys. Rev. C 109, 064627 (2024)R-matrix analysis: J. Skowronski

  • 23Na(p,p)23Na

    Compound nucleus 24Mg

    Proton scattering on sodium-23: the magnesium-24 levels through which 23Na(p,α) and 23Na(p,γ) destroy sodium in stars. · opens in about 3 s

    Work in progressR-matrix analysis: J. Skowronski

  • 3He(α,γ)7Be

    6Li(p,γ)7Be · 6Li(p,α)3He · 3He(α,p)6Li · 6Li(p,p)6Li · 3He(α,α)3He

    Compound nucleus 7Be

    Opens the branches of the pp chain that emit the 7Be and 8B solar neutrinos, and made most of the lithium after the Big Bang. · opens in about 6 s

    J. Skowronski, R. J. deBoer, T. Szücs, submitted to Phys. Rev. C (2026)R-matrix analysis: J. Skowronski

  • 4He(α,α)4He

    Compound nucleus 8Be

    Alpha–alpha scattering: the beryllium-8 states behind the first step of the triple-alpha process, which makes the carbon in stars. · opens in about 1 s

    Not yet publishedR-matrix analysis: J. Skowronski