Mon·Jul 1, 2024Monday·July 1, 2024

1. 01*

   Gamma decay of the ${}^{154}$Sm Isovector Giant Dipole Resonance: Smekal-Raman Scattering as a Novel Probe of Nuclear Ground-State Deformation

   J. Kleemann · N. Pietralla🇩🇪 · U. Friman-Gayer🇸🇪 · J. Isaak · O. Papst · K. Prifti · V. Werner🇩🇪 · A. D. Ayangeakaa🇺🇸 · T. Beck · G. Colò🇮🇹 · M. L. Cortés🇯🇵 · S. W. Finch🇺🇸 and 10 other authors

   Gamma decays of the isovector giant dipole resonance (GDR) of the deformed nucleus ${}^{154}$Sm from $2_1^{+}$-Smekal-Raman and elastic scattering were measured using linearly polarized, quasimonochromatic photon beams. The two scattering processes were disentangled through their distinct angular distributions. Their branching ratio and cross sections were determined at six excitation energies covering the ${}^{154}$Sm GDR. Both agree with the predictions of the geometrical model for the GDR and establish $\gamma$ decay as an observable sensitive to the structure of the resonance. Consequently, the data place strong constraints on the nuclear shape, including the degree of triaxiality. The derived ${}^{154}$Sm shape parameters $\beta =0.2926(26)$ and $\gamma =5.0(14)$ agree well with other measurements and recent Monte Carlo Shell-Model calculations.

   nucl-exnucl-thPRL(2025)·21 citations
2. 02*

   Calculation of crystal defects induced in CaWO${}_4$ by 100 eV displacement cascades using a linear Machine Learning interatomic potential

   Gabrielle Soum-Sidikov🇫🇷 · Jean-Paul Crocombette🇫🇷 · Mihai-Cosmin Marinica🇫🇷 · Corentin Doutre🇫🇷 · David Lhuillier🇫🇷 · Loïc Thulliez🇫🇷

   We determine the energy stored in the crystal defects induced by $\mathcal{O}(10-100)$\,eV nuclear recoils in low-threshold CaWO${}_4$ cryogenic detectors. A Machine Learning interatomic potential is developed to perform molecular dynamics simulations. We show that the energy spectra expected from Dark Matter and neutrino coherent scattering are affected by the crystal defects and we provide reference predictions. We discuss the special case of the spectrum of nuclear recoils induced by neutron capture, which could offer a unique sensitivity to the calculated stored energies.

   ↳ physics.ins-detcond-mat.mtrl-scihep-exnucl-exPRD(2025)·6 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.