Mon·Dec 22, 2025Monday·December 22, 2025

1. 01*

   Improved $S$-factor of the ${}^{13}$C(p,$\gamma$)${}^{14}$N reaction at $E_{\mathrm{p}}=$330-740 keV and parameters of resonances at 448 keV and 551 keV

   J. Skowronski🇮🇹 · E. Masha🇩🇪 · D.Piatti🇮🇹 · M. Aliotta🇬🇧 · D. Bemmerer🇩🇪 · A. Boeltzig🇩🇪 · A. Caciolli🇮🇹 · F. Cavanna · L. Csedreki · R. Depalo🇮🇹 · P. Hempel · M. Hilz and 14 other authors

   The ${}^{13}$C(p,$\gamma$)${}^{14}$N reaction is the second reaction of the CNO cycle. This cycle takes place in our Sun and fuels massive, Red, and Asymptotic Giant Branch stars. The ${}^{13}$C(p,$\gamma$)${}^{14}$N rate affects the final abundances of ${}^{12,13}$C and ${}^{19}$F nuclides, with impact on our understanding of the i- and s-process, giant star nucleosynthesis and mixing processes, and ultimately the chemical evolution of the Galaxy. Here, we report on a new measurement of the ${}^{13}$C(p,$\gamma$)${}^{14}$N cross-section, which has been performed at the Felsenkeller shallow-underground laboratory in Dresden (Germany). The present $S$-factor results agree at low energy with LUNA data but are about 20% lower than previous literature data over the whole energy range explored, $E=$310-680 keV. The narrow resonance corresponding to the 7966.9(5) keV excited state has been investigated and we report a new resonance strength, $\omega \gamma =$18(2) meV. In addition a new R-matrix fit is presented, from which new parameters for the broad resonance corresponding to the 8062.0(10) keV excited state are derived and a new extrapolation for the total $S$-factor down to zero energy is obtained, $S_{\mathrm{tot}}$(0) = 6.4(4) keV b. Finally a new reaction rate is calculated and reported here.

   nucl-exPRC(2025)·0 citations
2. 02*

   From closed shells to open shells: Coupled-cluster calculations of atomic nuclei

   F. Marino🇩🇪 · F. Bonaiti🇺🇸 · P. Demol🇧🇪 · S. Bacca🇩🇪 · T. Duguet🇫🇷 · G. Hagen🇺🇸 · G. R. Jansen🇺🇸 · T. Papenbrock🇺🇸 · A. Tichai🇩🇪

   Coupled-cluster theory is a powerful tool for first-principles calculations of atomic nuclei, enabling accurate predictions of nuclear observables across the Segrè chart. While coupled-cluster computations are especially efficient at shell closures, extensions have been developed to tackle open-shell nuclei, by exploiting the equation-of-motion method or by expanding the coupled-cluster wave function on top of a symmetry-breaking (either deformed or superfluid) reference state. In this study, we provide a comprehensive comparison of these different formulations applied to the calcium and nickel isotopes using nuclear two- and three-body interactions from chiral effective field theory. Based on ground-state energies, two-neutron separation energies, and two-neutron shell gaps, different coupled-cluster computations - based on symmetry-broken reference states and equation-of-motion techniques - offer consistent descriptions of bulk properties across medium-mass isotopic chains.

   ↳ nucl-thnucl-exPRC(2026)·6 citations
3. 03*

   Final SeaQuest results on the flavor asymmetry of the proton light-quark sea with proton-induced Drell-Yan process

   FNAL E906/SeaQuest Collaboration: C. H. Leung🇺🇸 · J. Dove🇺🇸 · K. Nagai🇺🇸 · K. Nakano🇯🇵 · S. Prasad🇺🇸 · A. S. Tadepalli🇺🇸 · C. A. Aidala🇺🇸 · J. Arrington🇺🇸 · C. Ayuso🇺🇸 · C. L. Barker🇺🇸 · W. C. Chang🇹🇼 · A. Chen🇺🇸 and 45 other authors

   The Fermilab E906/SeaQuest collaboration performed measurements of the Drell-Yan process using 120 GeV proton beams bombarding liquid hydrogen and liquid deuterium targets. A combined analysis of all collected data was performed to obtain the final results for the ${\sigma }_{pd}/2{\sigma }_{pp}$ Drell-Yan cross section ratio covering the kinematic region of $0.13<x<0.45$. The $x$-dependencies of $\bar{d}\left(x\right)/\bar{u}\left(x\right)$ and $\bar{d}\left(x\right)-\bar{u}\left(x\right)$ are extracted from these cross section ratios. It is found that $\bar{d}\left(x\right)$ is greater than $\bar{u}\left(x\right)$ over the entire measured $x$ range, with improved statistical accuracy compared to previous measurements. The new results on $\bar{d}\left(x\right)/\bar{u}\left(x\right)$ and $\bar{d}\left(x\right)-\bar{u}\left(x\right)$ are compared to various parton distribution functions and theoretical calculations.

   ↳ hep-exnucl-exPRL(2026)·2 citations
4. 04*

   Active learning emulators for nuclear two-body scattering in momentum space

   A. Giri🇮🇳 · J. Kim🇺🇸 · C. Drischler🇺🇸 · Ch. Elster🇺🇸 · R. J. Furnstahl🇺🇸

   We extend the active learning emulators for two-body scattering in coordinate space with error estimation, recently developed by Maldonado et al. [Phys. Rev. C 112, 024002], to coupled-channel scattering in momentum space. Our full-order model (FOM) solver is based on the Lippmann-Schwinger integral equation for the scattering $t$-matrix as opposed to the radial Schrödinger equation. We use (Petrov-)Galerkin projections and high-fidelity calculations at a few snapshots across the parameter space of the interaction to construct efficient reduced-order models (ROMs), trained by a greedy algorithm for locally optimal snapshot selection. Both the FOM solver and the corresponding ROMs are implemented efficiently in Python using Google's JAX library. We present results for emulating scattering phase shifts in coupled and uncoupled channels and cross sections, and assess the accuracy of the developed ROMs and their computational speedup factors. We also develop emulator error estimation for both the $t$-matrix and the total cross section. The software framework for reproducing and extending our results is publicly available. Together with our recent advances in developing active-learning emulators for three-body scattering, these emulator frameworks set the stage for full Bayesian calibrations of chiral nuclear interactions and optical models against scattering data with quantified emulator errors.

   ↳ nucl-thhep-phnucl-exphysics.data-anPRC(2026)·3 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.