PaperPanorama

Nuclear Experiment·nucl-ex

Thu·Jun 25, 2026

5 papers—1 primary·4 cross-listed

All5Primary1Cross-lists4
  1. 01

    Low lying excitations in Pm

    A. Pal🇮🇳 · S. Basak🇮🇳 · T. Bhattacharjee🇮🇳 · Nazira Nazir · G. H. Bhat🇮🇳 · S. Jehangir🇮🇳 · D. Kumar🇮🇳 · A. Saha🇮🇳 · S. S. Alam🇮🇳 · D. Banerjee · A. Das🇮🇳 · A. Adhikari🇮🇳 and 10 other authors

    The low lying excitations in odd-odd Pm have been studied through proton induced reaction with an array of five Compton suppressed Clover HPGe and one segmented planar Ge detectors. The relative excitation functions for the observed rays have been studied using singles data at two beam energies of 8~MeV and 9~MeV. 16 new rays and 15 new levels have been placed in the level scheme of Pm based on coincidence data. The relative intensities for the observed rays have been determined using total and gated projections. Tentative spin-parity assignments were made to few low lying excitations of Pm, using limited angular distribution data and other information. Lifetimes were estimated for two excited levels in this nucleus using using generalized centroid difference analysis, applied in the nanosecond range, with Ge detectors. Large basis shell model and projected shell model calculation were performed to interpret the experimentally observed levels. The present work indicates 1 ground state, a 2 state close to the ground state (50~keV) and a low lying 6 isomeric state in this odd-odd nucleus along with emerging band structures developed with two quasiparticle configurations.

    nucl-exnucl-th0 citations
  2. 02

    Empirical-Bayes Unfolding of -ray Spectra

    A. H. Mjøs · E. Lima · A. Kvellestad🇳🇴 · A. C. Larsen🇳🇴 · M. Hjorth-Jensen🇳🇴

    Unfolding observed -ray spectra is an ill-conditioned Poisson inverse problem. Detector response effects and finite energy resolution make distinct non-negative emitted -ray spectra nearly indistinguishable after forward mapping, so direct inversion can strongly amplify statistical fluctuations. Here, we present an empirical-Bayes hierarchical unfolding method that preserves the Poisson counting structure, enforces non-negativity, and incorporates background through a joint ON/OFF likelihood. The prior on the emitted spectrum is centered on an automatically selected Richardson-Lucy reference spectrum, with an adaptive width that remains broad in weakly constrained regions. Posterior inference is performed with the No-U-Turn Sampler, and simultaneous uncertainty bands are reported for the resolution-limited unfolded spectrum. Our Bayesian method provides a robust and extensible framework for uncertainty quantification in unfolding, and a direct comparison with a recent frequentist regularized maximum-likelihood method gives highly consistent unfolded spectra in representative high- and low-statistics cases.

    ↳ astro-ph.IMnucl-exphysics.data-anphysics.ins-det0 citations
  3. 03

    Ab initio calculations of parity-violating electron scattering off Ca and Pb

    Frederic Noël🇨🇭 · Matthias Heinz🇺🇸 · Martin Hoferichter🇨🇭 · Takayuki Miyagi🇯🇵 · Achim Schwenk🇩🇪

    Parity-violating electron scattering off nuclei both serves as a low-energy precision probe to test electroweak interactions and allows one to access neutron distributions inside nuclei. It has implications for strong interactions in dense neutron-rich environments, also providing constraints for the properties of matter in neutron stars. Precision measurements are available for Ca and Pb by the CREX and PREX collaborations, respectively, and their interpretation requires advanced nuclear-structure calculations to draw firm conclusions. We perform the first ab initio calculations of the parity-violating asymmetry based on nuclear forces from chiral effective field theory, fully including corrections due to Coulomb distortion effects. Based on these results, we critically reexamine correlation analyses employed to infer weak radii and quantify the resulting tensions between ab initio and experimental results. We find that ab initio calculations prefer values of slightly smaller and larger than observed for Ca and Pb, respectively, with a global significance of . Using theoretically consistent inputs for charge and weak densities, we infer from the experimental a neutron skin of Pb of fm, substantially smaller than that reported by PREX II.

    ↳ nucl-thastro-ph.HEhep-exhep-ph+12 citations
  4. 04

    The renormalization of the shell-model neutrinoless double-beta decay operator starting from effective field theory (I)

    L. Coraggio🇮🇹 · G. De Gregorio🇮🇹 · S. L. Lyu🇮🇹 · N. Itaco🇮🇹

    In this work, we approach for the first time the task to perform a shell-model calculation of the matrix element for the neutrinoless double-beta decay, within a fully-consistent framework where the expressions of the nuclear Hamiltonian and of the decay operators have been derived through chiral perturbation theory. More precisely, the effective shell-model Hamiltonian and all transition operators have been constructed by way of the many-body perturbation theory, and then employed to calculate both spectroscopic properties of the nuclei involved in the decays under our consideration - namely 48Ca, 76Ge, and 82Se -, as well as the nuclear matrix elements of the electromagnetic and neutrinoless double-beta decays. We also present a study of the convergence properties of the calculated matrix elements in order to provide the elements for an estimate of the theoretical uncertainty.

    ↳ nucl-thhep-exnucl-ex0 citations
  5. 05

    Positron-Emitting and Electron-Capturing Double-Beta Processes in the Standard Model and Beyond

    Lukáš Gráf🇨🇿 · Jenni Kotila🇫🇮 · Oliver Scholer🇩🇪

    We study positron-emitting and electron-capturing double-beta-decay modes as probes complementary to the usual double beta decay. Motivated by the proposed NuDoubt++ experiment, we analyze the candidate isotopes Kr, Cd, and Xe, providing nuclear matrix elements and phase-space factors for both neutrinoful and neutrinoless modes. For the Standard-Model channels, we find that ECEC and EC are the most experimentally accessible, whereas remains strongly phase-space suppressed. For the neutrinoless channel, we interpret a projected sensitivity of y in terms of dimension-seven SMEFT operators and find sensitivity to lepton-number-violating new-physics scales of order 1-100 TeV. We further show that measurements in multiple isotopes can help to resolve degeneracies in multi-operator scenarios, making positron-emitting double-beta searches a useful complement to conventional neutrinoless double beta decay experiments.

    ↳ hep-phnucl-exnucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE