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Nuclear Theory·nucl-th

Monday·July 14, 2025

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    Conformal prediction for uncertainties in nucleon-nucleon scattering

    Habib Yousefi Dezdarani🇨🇦 · Ryan Curry🇨🇦 · Alexandros Gezerlis🇨🇦

    Conformal prediction is a distribution-free and model-agnostic uncertainty-quantification method that provides finite-sample prediction intervals with guaranteed coverage. In this work, for the first time, we apply conformal-prediction to generate uncertainty bands for physical observables in nuclear physics, such as the total cross section and nucleon-nucleon phase shifts. We demonstrate the method's flexibility by considering three scenarios: (i) a pointwise model, where expansion coefficients in chiral effective field theory are treated as random variables; (ii) a Gaussian-process model for the coefficients; and (iii) phase shifts at various energies and partial waves calculated using local interactions from chiral effective field theory. In each case, conformal-prediction intervals are constructed and validated empirically. Our results show that conformal prediction provides reliable and adaptive uncertainty bands even in the presence of non-Gaussian behavior, such as skewness and heavy tails. These findings highlight conformal prediction as a robust and practical framework for quantifying theoretical uncertainties.

    nucl-thphysics.data-anPRC(2026)·4 citations
  2. 02

    Evaluation of bound-state -decay half-lives of fully ionized atoms

    Priyanka Choudhary · Chong Qi

    Bound-state -decay is a rare radioactive process where the created electron is trapped in an atomic orbital instead of being emitted. It can be observed in highly ionized atoms in particular when normal beta decay is energetically forbidden, but bound-state decay is still possible. In this work we present a systematic theoretical study on the bound-state -decay of fully ionized atoms where key nuclear inputs include the nuclear matrix elements (expressed through values) and the lepton phase-space volume function. We present a method to evaluate nuclear matrix elements for fully forbidden transitions in neutral atoms, from the inverse electron capture process using the Takahashi-Yokoi model and account for the impact of electron capture to different atomic orbitals on the resulting half-lives. Decay rates for bound-state -decays of nuclei Dy, Ir, Au, Tl, Tl, At, Rn, Am, and Bk are calculated, where the normal beta decay is forbidden. In addition, we compute the bound-state decay rates for nuclei Re, Ac, and Ra, observing enhancements by factors of to relative to their neutral-atom counterparts. Our results show that the half-lives of certain bare nuclei are significantly shorter than those of the corresponding neutral atoms, identifying them as promising candidates for future experimental investigation. The theoretically predicted half-lives of the bound-state decay could provide valuable inputs for various astrophysical studies.

    nucl-thEPJA(2026)·1 citation
  3. 03

    Ab initio lattice study of neutron-alpha scattering with chiral forces at N3LO

    Serdar Elhatisari · Fabian Hildenbrand · Ulf-G. Meißner

    We present the first ab initio lattice calculation of neutron-alpha (-) scattering using nuclear lattice effective field theory (NLEFT) with chiral interactions at next-to-next-to-next-to-leading order (N3LO). Building on the high-fidelity chiral Hamiltonian introduced in Ref. [1], we compute scattering phase shifts in the - and -wave channels using the Lüscher finite-volume method. Our results demonstrate excellent agreement with empirical -matrix phase shifts in the and channels, while revealing persistent discrepancies in the channel for neutron energies above 5 MeV. To systematically investigate these discrepancies, we construct and analyze a simplified neutron-alpha toy model, demonstrating that these discrepancies are not due to the use of the Lüscher finite-volume method. Additionally, we revisit our three-nucleon (3N) force fitting procedure, explicitly incorporating neutron-alpha scattering data through comprehensive Markov Chain Monte Carlo (MCMC) sampling. This analysis confirms the stability of nuclear binding-energy predictions and highlights the need for further refinements in the lattice N3LO three-nucleon forces to fully describe neutron-alpha scattering in the challenging channel.

    nucl-thhep-latnucl-exJ.Phys.G(2025)·12 citations
  4. 04

    The breakdown scale of pionless effective field theory in the three-nucleon sector

    Andreas Ekström🇸🇪 · Lucas Platter🇺🇸

    We make order-by-order predictions of neutron-deuteron total cross sections up to next-to-next-to-leading order in pionless effective field theory. Using Bayesian methods, we infer a posterior distribution for the breakdown scale. The result shows a mode near 100 MeV, and a combined analysis with neutron-proton scattering further sharpens the inference, placing the mode close to the pion mass scale, consistent with the expected range of pionless effective field theory.

    nucl-thPRC(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE