PaperPanorama

Nuclear Experiment·nucl-ex

Mon·Sep 21, 2026

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 01

    Direct measurement of Enhanced octupole collectivity in 148Dy

    P. Spagnoletti · V. Vedia · E. Yuksel · Y. X. Yu · G. J. Fu · R. Umashankar · G. Andreetta · C. Andreoiu · A.A. Avaa · G.C. Ball · V. Bildstein · S. Buck and 27 other authors

    Excited states in Dy were populated via decay of Ho using the GRIFFIN spectrometer at the TRIUMF ISAC-I facility. A combined measurement of the mean lifetime of the level using the Generalized Centroid Difference (GCD) method and branching fraction of the -ray decay has been performed. From these results, an enhanced electric octupole transition strength of 46(3)~W.u. has been determined in Dy. This is the largest measured value across the closed neutron shell at and provides direct evidence of enhanced octupole collectivity beyond . The evolution of the strength along the isotonic chain is compared with quasiparticle random-phase approximation (QRPA) calculations using the SkI3 and SkM Skyrme energy-density functionals, as well as with large-scale shell-model (SM) calculations. This result extends the boundaries of enhanced octupole collectivity far from the so-called `octupole magic numbers' and .

    nucl-ex
  2. 02

    First observation of the fine structure of the Pygmy Dipole Resonance in a nucleus away from stability via the decay of Rb to Sr

    P. Spagnoletti · M. Ramalho · S. Tahtela · E. Kauppinen · J. Suhonen · C. Andreoiu · M. Scheck · V. Vedia · Z. Ahmed · D. Annen · G.C. Ball · G. Benzoni and 43 other authors

    A comprehensive -ray spectroscopy study of excited states in Sr populated via decay of Rb (, ~keV) was performed with the GRIFFIN spectrometer at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. The high -ray efficiency of the GRIFFIN spectrometer combined with the intense rubidium beams produced allowed for 864 -ray transitions to be placed in the level scheme with 190 excited levels populated, most of them identified for the first time. The excitation energies of low-spin states in Sr are well reproduced by large-scale Shell Model calculations up to 5~MeV. The -feeding intensities are in very good agreement with results from a recent study employing Modular Total Absorption Spectroscopy, indicating a significant suppression of the Pandemonium effect. The experimental picture reveals the energy level dependence of log~ values in unprecedented detail. These log~ values are well reproduced by Multiple-Commutator Model calculations that identify the features in the excited levels' wavefunctions that enable the population of high-lying levels with a low effective Q-value that belong to the Pygmy Dipole Resonance.

    nucl-ex
  3. 03

    Automated Physics-Informed Neural-Networks-Based Calibration of Highly Segmented Silicon Telescopes

    M. Rejmund · A. Lemasson · P. Morfouace · D. Ramos · J. Taieb · J. D. Frankland

    Transfer and multi-nucleon transfer reactions are essential tools for probing nuclear structure and reaction dynamics, requiring precise determination of the identity, energy, and emission angles of reaction products. The increasing granularity of modern silicon telescope arrays enhances experimental capabilities but challenges detector calibration, as conventional channel-by-channel approaches become inefficient and difficult to scale. In this work, we present a fully automated, physics-informed calibration framework based on neural networks, specifically designed for highly segmented silicon detector arrays. The method formulates calibration as a global optimization problem, in which detector gains and geometrical corrections are determined simultaneously by minimizing the width of the reconstructed excitation energy under two-body kinematics constraints. The approach relies exclusively on experimental data and well-established physical principles, without requiring explicit modeling of detector response. A distinctive feature is the use of multiple neural network sub-models sharing a common loss function with embedded physics constraints, enabling coherent and self-consistent calibration across all detector channels. This strategy ensures scalability, robustness, and reproducibility, making it particularly suitable for next-generation detector systems with increasing complexity. The performance of the method is demonstrated using experimental data from the Particle-Identification Silicon-Telescope Array (PISTA) in high-resolution fission studies in inverse kinematics. The results show excellent agreement with theoretical kinematics, high-quality particle identification, and a significant improvement in calibration efficiency. The proposed framework provides a general and adaptable solution for the calibration of complex detector systems in modern nuclear physics experiments.

    ↳ physics.ins-detcs.LGnucl-ex
  4. 04

    Jet transport coefficients associated with fermionic two-point correlators in a weakly-coupled plasma

    Shay Duddy · Lukas Opitz · Amit Kumar · Gojko Vujanovic

    A new set of jet-medium transport coefficients stemming from jet-medium exchanges involving Glauber quarks encoded in [Phys. Rev. C 111, 054913 (2025), Phys. Rev. C 113, 055207] are obtained by computing the tree-level leading-order scattering rates and their moments using the approach developed in Refs. [arxiv 2608.17160, arxiv 2608.17161]. Sizeable deviations away from the leading logarithmic dependence of jet-medium transport coefficients and scattering rate are observed here, as previously mentioned in Refs.[arxiv 2608.17160, arxiv 2608.17161]. A closed-form expression for accurate to \% or better is obtained, enabling our approach to be used within Monte Carlo simulations of jet-medium interactions. Monte Carlo simulations incorporating are sensitive to flavor hydrodynamization dynamics as the medium created in nucleus-nucleus collisions transitions from the early-time Glasma dynamics to the quark-gluon plasma fluid.

    ↳ hep-phnucl-exnucl-th