Focus on:  Hide Contributions
Back to Conference View
Login

Nuclear Masses in Astrophysics for the Next 25 Years

→ US/Eastern
1221 A/B (Facility for Rare Isotope Beams, East Lansing, MI, USA)

1221 A/B

Facility for Rare Isotope Beams, East Lansing, MI, USA
Alfredo Estrade (CMU), Sam Porter (University of Notre Dame)
Description

Nuclear masses play a central role in nuclear astrophysics, significantly impacting the origin of the elements and observables used to constrain ultradense matter. A variety of techniques are available to meet this need, varying in their emphasis on precision and reach from stability. These are complemented by theory tools that identify key masses and extrapolate beyond experimental reach.

The nuclear astrophysics community has regularly met to discuss the importance of nuclear masses and the path forward for the field, building connections between techniques, research groups across continents, and experiment to theory. In recent years there have been major advances in experiment, nuclear theory, and computational astrophysics. This workshop has the goal of training and showcasing the next generation of nuclear mass spectrometrists, summarizing the state-of-the-art in nuclear mass measurement and theory, and charting a course for the next 25 years of nuclear masses for nuclear astrophysics.

This is the second workshop in a series started with a first meeting in Darmstadt (Germany) in August 2025. It will have the specific goals of producing a whitepaper charting the course to leverage the complementarity of experimental techniques, while using nuclear and astrophysics theory to guide measurements in order to maximize science output and ultimate reach across the nuclear landscape. 

The meeting will take place at the Facility for Rare Isotope Beams at Michigan State University. Limited financial support to partially cover travel expenses will be available thanks to the event's sponsorship by CeNAM.

The wokshop will host a limited number of participants. If you are interested to join please sign up through the registration page.

 

 

Organizing Committee:
Alfredo Estrade
Sam Porter

Advisory Committee:
Klaus Blaum
Anu Kankainen
Yury Litvinov
Zachary Meisel
Hendrik Schatz
Nikolai Shchechilin 

FRIB_Entrance.jpg
  • Monday 11 May
    • 09:00 → 10:20
      Presentations: Astrophysics
      • 09:00
        Welcome 5m
      • 09:05
        The r process: nature’s tour guide of the unmapped nuclear chart 25m

        The astrophysical rapid neutron capture process (r-process) ventures far from the stable species found on Earth. Experimental facilities have made impressive inroads towards pinning down the properties of more exotic, neutron-rich nuclei, but the map of the nuclear chart is far from complete, with the r process being the case we know to have wandered furthest into uncharted territory. We will discuss statistical methods predicting masses which align nucleosynthesis predictions with Solar data, and their potential to constrain the origin of the rare-earth peak when coupled with lanthanide mass measurements. Further opportunities for addressing key science questions exist with studies of species near shell closure N=126, which controls the production of elements such as gold and platinum. Excitingly, predictions for masses in this exotic region have now been approached by ab initio nuclear theory with interesting implications for the r-process third abundance peak. This talk will also demonstrate how theoretical predictions for other r-process observables (e.g. stellar and meteorite abundances, mergers transients such as MeV gamma-rays) are sensitively tied to the nuclear mass model applied, and highlight opportunities for mass measurements to contribute to our understanding of future observations.

        Speaker: Nicole Vassh (TRIUMF)
      • 09:30
        Nuclear Masses For r-process Nucleosynthesis 25m
        Speaker: Mengke Li (UC Berkeley)
      • 09:55
        The end of the beginning of nuclear masses for the rp-process 20m

        In the beginning, X-ray burst modeling was data-poor and the number of high-impact nuclear mass measurement opportunities were many. Today the situation has changed. Opportunities still exist, but they are more subtle, requiring consideration of an expanded set of astrophysical conditions and more complex observables. I will argue that we are not at the end of rp-process nuclear mass measurements, nor even the beginning of the end, but perhaps the end of the beginning.

        Speaker: Zach Meisel (Ohio University)
        2026_NuclMassesAstro_RPprocessMeisel.pdf
    • 10:20 → 10:50
      Coffee break
    • 10:50 → 12:20
      Presentations: Theory
      • 10:50
        TBD 25m
        Speaker: Nikolai Shchechilin (Universite Libre de Bruxelles)
      • 11:15
        Latest developments in the Brussels microscopic mass models 25m

        The rapid neutron-capture process (or r-process) is responsible for the production of about half of the elements heavier than iron in the Universe and
        is expected to take place in neutron star mergers and possibly in exploding
        massive stars. To estimate the composition of the ejecta, a reaction network
        involving about 6000 neutron-rich nuclei with all reactions of interest needs
        to be calculated. The major nuclear transmutations include neutron captures,
        photoneutron emissions, beta-decays as well as fission processes. Since mass
        differences set the energy scale in all nuclear reactions, nuclear binding energies
        are crucial ingredients to estimate reaction rates. For the r-process in particular, mass differences govern the competition between neutron capture and
        photoneutron emission. Unfortunately, only about 2500 nuclear masses have
        been measured so far. Since experimental efforts have so far not been able to
        access the neutron-rich nuclei produced by the r-process during the neutron
        irradiation, theoretical predictions are fundamental to fill the gap.

        Models built on energy density functionals (EDF) have been successful pro-
        viding a microscopic description of the atomic nucleus at a reasonable numerical
        cost. Over the last five years, the state-of-the-art BSkG (Brussels-Skyrme-on-a-
        Grid) family of Skyrme-EDF parametrizations has been developed. These mod-
        els go beyond the usual limitations of traditional Skyrme-EDF parametrizations
        by accounting for highly complex nuclear shapes through symmetry breaking
        during their adjustment. Starting with BSkG3 [1], they have been fitted to all
        known masses, as well as to actinide fission barriers and infinite nuclear mat-
        ter properties. This allows these models to accurately predict nuclear masses,
        with root-mean-square deviations of about 0.63 MeV, making them some of the
        best mass models available. During the last year, a significant number of developments have been made. On the one hand, our latest model, BSkG5 [2],
        has marked the first time that a Skyrme N2LO parametrization has been able
        to reproduce nuclear masses with root-mean-square deviations below 0.7 MeV.

        On the other hand, large-scale calculations of fission barriers and spontaneous-
        fission half-lives have been performed with BSkG3 [3], yielding the most accurate

        results obtained so far by any microscopic method.
        In this talk, I will present our latest mass model, BSkG6. This new model,
        also based on the Skyrme N2LO functional, incorporates new microscopic dynamical terms that provide a better description of beyond-mean-field contributions to the binding energy while maintaining a moderate computational cost.

        [1] G. Grams, W. Ryssens, G. Scamps, S. Goriely, and N. Chamel, “Skyrme-
        Hartree-Fock-Bogoliubov mass models on a 3D mesh: III. From atomic
        nuclei to neutron stars”, The European Physical Journal A 59, 270 (2023).
        [2] G. Grams et al., “Skyrme-hartree-fock-bogoliubov mass models on a 3d
        mesh: v. the n2lo extension of the skyrme edf”, arXiv preprint arXiv:2601.05968
        (2026).
        [3] A. Sánchez-Fernández, S. Bara, W. Ryssens, and S. Goriely, “Accurate spontaneous fission half-lives from a microscopic large-scale nuclear structure model”, Physics Letters B, 140287 (2026).

        Speaker: Luis Gonzáles Miret
      • 11:40
        Nuclear Masses at the Predictive Frontier 25m

        Mass is a fundamental observable in nuclear physics, encoding the integrated effect of nuclear interactions and anchoring a range of applications from astrophysics to tests of the Standard Model. Yet of the roughly 7,000 nuclei expected to be bound, only about half have ever been measured, leaving the rest to be predicted by theory. In this talk I survey today's modeling approaches, noting the rise of scientific machine learning as a complementary tool. I focus on how the field is moving from precise fits toward genuinely predictive, uncertainty-aware mass models. I close with a look ahead at how rapid integration of new measurements from facilities like FRIB will define the next decade of research with nuclear masses.

        Speaker: Matthew Mumpower
    • 12:30 → 14:00
      Lunch
    • 14:00 → 15:20
      Presentations: Data
    • 15:20 → 15:50
      Coffee break
    • 15:50 → 17:20
      Break-out group discussion
  • Tuesday 12 May
    • 09:00 → 10:45
      Presentations: Experiments
      • 09:00
        Mass measurements at the S800 25m
        Speaker: Justin Placido
        Placido_MassesAstro25Years.pdf
        Placido_MassesAstro25Years.pptx
      • 09:25
        Current Capabilities and Future Advancement for Astrophysical Mass Measurements with LEBIT at FRIB 25m

        Determining the exact methods of nucleosynthesis, in which elements are produced by a variety of astrophysical processes, remains a crucial and open question in nuclear science. Nuclear mass data is a key input for astrophysical models, which constrain nucleosynthesis reaction pathways, impacting the abundance distribution of produced isotopes. As such, accurate and precise mass data in exotic regions of the nuclear chart where these production methods occur are of critical importance for the field. With the Facility for Rare Isotope Beams (FRIB) now on-line, nuclei at and near the proton- and neutron- driplines are within reach for precision mass measurements with the Low Energy Beam and Ion Trap (LEBIT) facility. An overview will be given of recent experiments that have demonstrated our capability of measuring nuclei near the proton dripline, as well as isomers of nuclei. Additionally, ongoing projects which will extend the reach of the LEBIT facility in the new FRIB era will be presented.

        Speaker: Hannah Erington (Facility for Rare Isotope Beams (Michigan State University))
        Erington_NMW2026.pdf
        Erington_NMW2026.pptx
      • 09:50
        Weighing the Nucleus: European Trapped-Ion Efforts for Astrophysics 25m

        Precision measurements of nuclear masses provide critical input for modeling nucleosynthesis pathways and the structure of exotic nuclei far from stability. In this talk, I will present recent advances in trapped-ion mass spectrometry across European facilities, highlighting key results and methodological developments that have significantly improved accuracy and reach. A few highlights of how these measurements constrain astrophysical processes and refine theoretical models will be shown. I will also outline ongoing efforts and future directions aimed at extending precision mass measurements toward ever more short-lived and rare isotopes.

        Speaker: Klaus Blaum (Max Planck Society (DE))
        Masses Europe Blaum 2026.pdf
      • 10:15
        Precision mass measurements for nuclear astrophysics at ATLAS 25m

        ATLAS, the Argonne Tandemless Linac Accelerator System, has a long history of precision mass measurements for nuclear astrophysics, most recently focusing on mass measurements for the r-process rare earth peak at CARIBU with the Canadian Penning Trap. Into the next 25 years, ATLAS is developing new capabilities like nuCARIBU and the N=126 Factory which will enable further campaigns of mass measurements using the CPT and MR-TOF-MS

        Speaker: Adrian Valverde
    • 10:45 → 11:15
      Coffee break
    • 11:15 → 12:20
      White paper discussion
      • 11:15
        White Paper: astrophysics section 15m
      • 11:30
        White Paper: theory section 15m
      • 11:45
        White Paper: experiments section 15m
      • 12:00
        White Paper: data section 15m
        NuclearData_Kondev.pdf
    • 12:30 → 14:00
      Lunch
    • 14:00 → 15:20
      Break-out group discussion
    • 15:20 → 15:50
      Coffee break
    • 15:50 → 17:30
      White paper discussion
      • 15:50
        White Paper: astrophysics section 25m
      • 16:15
        White Paper: theory section 25m
      • 16:40
        White Paper: experiments section 25m
      • 17:05
        White Paper: data section 25m
  • Wednesday 13 May
    • 09:00 → 10:20
      Break-out group discussion
    • 10:20 → 10:50
      Coffee break
    • 10:50 → 12:20
      White paper discussion
      • 10:50
        White Paper: Introduction and conclusions 40m
      • 11:30
        White Paper: writing tasks 40m