Thu·Jun 26, 2025Thursday·June 26, 2025

1. 01*

   Single-event neutron time-of-flight spectroscopy with a petawatt-laser-driven neutron source

   M. A. Millán-Callado · S. Scheuren · A. Alejo🇬🇧 · J. Benlliure🇪🇸 · R. Beyer · T. E. Cowan🇩🇪 · B. Fernández🇪🇸 · E. Griesmayer · A. R. Junghans🇩🇪 · J. Kohl · F. Kroll · J. Metzkes-Ng and 13 other authors

   Fast neutron-induced nuclear reactions are crucial for advancing our understanding of fundamental nuclear processes, stellar nucleosynthesis, and applications, including reactor safety, medical isotope production, and materials research. With many research reactors being phased out, compact accelerator-based neutron sources are becoming increasingly important. Laser-driven neutron sources (LDNSs) offer unique advantages -- ultrashort neutron pulsees for superior energy resolution, high per-pulse flux, and a drastically reduced footprint. However, their use in single-event fast neutron spectroscopy remains unproven, requiring stable multi-shot operation and detectors capable of functioning in the extreme environment of petawatt-class laser-plasma interactions. Here, we present a proof-of-concept experiment at the DRACO~PW laser in a pitcher-catcher configuration, stably producing 6-7e7 neutrons/shot with energies above 1 MeV, over more than 200 shots delivered at a shot-per-minute rate. Neutron time-of-flight measurements were performed using a single-crystal diamond detector, which is located only 1.5 m away from the source and capable of resolving individual neutron-induced reactions. Observed reaction rates are consistent with Monte Carlo simulations inferred by real-time diagnostics of accompanying gamma, ion, and electron fluxes. With the recent advances in repetition rate, targetry, and ion acceleration efficiency, this work establishes LDNSs as a promising, scalable platform for future fast neutron-induced reaction studies, particularly for measurements involving short-lived isotopes or requiring high instantaneous neutron flux.

   nucl-exphysics.plasm-phNature Commun.(2026)·0 citations
2. 02*

   Structure of odd-A Ag isotopes studied via algebraic approaches

   Stanimir Kisyov · Stefan Lalkovski🇧🇬

   The structure of the odd-$A$ silver isotopes ${}^{103-115}$Ag is discussed within the frame of the Interacting boson-fermion model (IBFM). An overview of their key properties is presented, with particular attention paid to the $"$J-1 anomaly$"$, represented by an abnormal ordering of the lowest 7/2${}^{+}$ and 9/2${}^{+}$ states. By examining previously published data and newly performed calculations, it is demonstrated that the experimentally known level schemes and electromagnetic properties of ${}^{103-115}$Ag can be reproduced well within IBFM-1 by using a consistent set of model parameters. The contribution of different single-particle orbitals to the structure of the lowest-lying excited nuclear states in ${}^{103-115}$Ag is discussed. Given that the $J$-1 anomaly brings down the 7/2${}^{+}$ level from the $j^{-3}$ multiplet to energies which can be thermally populated in hot stellar environments, the importance of low-lying excited states in odd-$A$ silver isotopes for astrophysical processes is outlined.

   ↳ nucl-thnucl-exSymmetry(2025)·1 citation
3. 03*

   Extracting the kinetic freeze-out properties of high energy pp collisions at the LHC with event shape classifiers

   Jialin He🇨🇳 · Xinye Peng🇨🇳 · Zhongbao Yin🇨🇳 · Liang Zheng🇨🇳

   Event shape measurements are crucial for understanding the underlying event and multiple-parton interactions (MPIs) in high energy proton-proton (pp) collisions. In this paper, the Tsallis Blast-Wave model with independent non-extensive parameters for mesons and baryons, was applied to analyze transverse momentum spectra of charged pions, kaons, and protons in pp collision events at $\sqrt{s}=13$ TeV classified by event shape estimators relative transverse event activity, unweighted transverse spherocity, and flattenicity. Our analysis reveals consistent trends in the kinetic freeze-out temperature and non-extensive parameter across different collision systems and event shape classes. The use of diverse event-shape observables in pp collisions has significantly expanded the accessible freeze-out parameter space, allowing for a more comprehensive exploration of its boundaries. Among these event shape classifiers, flattenicity emerges as a unique observable for disentangling hard process contributions from additive MPI effects, allowing the isolation of collective motion effects encoded by the radial flow velocity. Through the analysis of the interplay between event-shape measurements and kinetic freeze-out properties, we gain deeper insights into the mechanisms responsible for flow-like signatures in pp collisions.

   ↳ hep-phnucl-exCPC(2026)·1 citation

* 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.