PaperPanorama

Nuclear Experiment·nucl-ex

Fri·Jul 17, 2026

7 papers—1 primary·6 cross-listed

All7Primary1Cross-lists6
  1. 01

    Investigation of hadronic effects on resonance productions in small collision systems using the EPOS4 model

    Hyunji Lim🇰🇷 · Bong-Hwi Lim🇯🇵 · Minjung Kim🇨🇭 · Sanghoon Lim🇰🇷

    Recent experimental results in high-multiplicity proton-proton (pp) collisions have suggested the possible emergence of collective behavior and medium-like effects previously considered characteristic of heavy-ion collisions. Resonance production provides a sensitive probe of such effects, as resonance yields and transverse-momentum distributions can be modified by hadronic interactions occurring between chemical and kinetic freeze-out. In this study, these effects are investigated using the EPOS4 event generator, in which hadronic final-state interactions are modeled through the UrQMD transport approach. By comparing calculations performed with and without UrQMD, the impact of hadronic interactions on resonance production is evaluated. In addition, the UrQMD contributions are separated into regeneration and rescattering, enabling a detailed investigation of both resonance production enhancement and the loss of reconstructible resonance signals. The analysis is performed for various mesonic and baryonic resonances with different lifetimes in pp collisions at LHC energies and is extended to p-O, O-O, and Pb-Pb collisions to study the system-size dependence of hadronic-phase effects. The results show that resonance production is governed by the competition between regeneration and rescattering, whose relative importance depends strongly on the resonance species, transverse momentum, and collision system. While rescattering suppresses reconstructible short-lived resonance signals, regeneration can significantly enhance the yields of several resonance species, particularly baryonic resonances. These findings demonstrate that hadronic interactions can play an important role even in small collision systems and highlight the need to measure resonances with different lifetimes and quantum numbers to constrain the dynamics and lifetime of the hadronic phase across collision systems.

    nucl-exnucl-th0 citations
  2. 02

    Bayesian Inference for Extracting Barrier Distributions from Fusion Excitation Functions

    Aaron Philip · Pablo Giuliani🇺🇸 · Kyle Godbey🇺🇸

    Barrier distributions encode rich information about the structure and dynamics of fusing nuclei, but extracting them from experimental fusion cross sections requires an estimate of the fusion excitation function's second derivative. In this work we approach the task of extracting barrier distributions with uncertainty estimates from sparse experimental measurements as a Bayesian inference problem. We introduce a method based on AutoBNN, an interpretable Bayesian machine learning framework, to provide a robust statistical approach for analyzing fusion excitation functions. Benchmarking against Gaussian process regression on simulated excitation functions that span a wide range of realistic experimental conditions, we find that AutoBNN more faithfully recovers the underlying barrier distribution and reports well-calibrated uncertainties. We then apply the AutoBNN method to four experimentally measured heavy-ion fusion reactions where it mitigates spurious above-barrier structure and constrains existing predictions. Alongside these results, we have developed a user-friendly software implementation of our method, facilitating its application to future heavy and light-ion fusion experiments.

    ↳ nucl-thnucl-ex0 citations
  3. 03

    Impact of tensor-rank components of chiral three-nucleon forces on the single-particle structure of calcium isotopes

    Tokuro Fukui · Giovanni De Gregorio🇮🇹 · Angela Gargano🇮🇹 · Chi Zhang🇨🇳 · Furong Xu🇨🇳

    Background: Chiral three-nucleon forces (3NFs) play a key role in the microscopic description of nuclear shell evolution. A recent work introduced an irreducible tensor decomposition of the chiral 3NF at next-to-next-to-leading order and showed that, in -shell nuclei, the enhancement of the -- spin--orbit (SO) splitting is mainly driven by its rank-1 component. Purpose: We extend the aforementioned analysis to the shell to investigate whether the same mechanism persists in a heavier valence space, and how the different tensor-rank components of the 3NF affect structure properties of calcium isotopes. Methods: Effective shell-model Hamiltonians for neutrons outside the doubly magic Ca core are derived from chiral two-nucleon force plus 3NF. The latter is progressively included through its rank- components (), allowing us to isolate their impact on the evolution of the neutron single-particle structure. Results: The significant enhancement of the SO splittings for both and orbitals produced by the chiral 3NF is mainly induced by its rank-1 component. The rank-2 term gives a smaller contribution, while the rank-3 term is negligible. The rank-0 component, and to a lesser extent the rank-1 component, are found to play an important role in determining the spacings between orbitals with different orbital angular momenta. All modifications induced by the 3NF in the single-particle structure have a relevant impact on the shell-closure properties of Ca. Conclusions: The dominance of the rank-1 two-pion-exchange component of the 3NF in explaining the enhancement of SO splitting -- previously identified in the shell -- persists in the shell. Observed effects of the 3NF related to the different angular-momentum dependence of the orbitals are shown to arise essentially from their rank-0 and rank-1 components.

    ↳ nucl-thnucl-ex0 citations
  4. 04

    Universal Properties of Near-Threshold Single-Neutron Resonances

    Myungkuk Kim · Young-Ho Song · Hans-Werner Hammer🇩🇪 · Youngman Kim🇰🇷 · Dean Lee🇺🇸 · Yuan-Zhuo Ma🇺🇸

    We establish universal width predictions for near-threshold single-neutron resonances in partial waves. Our results go beyond Wigner's well-known scaling behavior of cross sections near threshold. We show that the finite square-well potential exhibits discrete scale invariance at zero energy. From this fact, we derive an analytic baseline for the resonance width that depends only on geometry, angular momentum, and resonance energy, and not on internal short-distance nuclear details or radial excitation. This is a nontrivial property that is unique to the finite square-well potential and does not occur for other potentials. Application to observed p-wave and d-wave resonances demonstrates that the square-well result provides a robust baseline. We show that discrete scale invariance erases radial-node information in the sharp-boundary limit, but realistic Woods-Saxon diffuseness breaks this invariance, suppressing the reduced width by a factor sensitive to the internal radial excitation. These results provide a simple geometric benchmark for identifying when observed neutron resonances are controlled by universal threshold physics and when they exhibit systematic deviations driven by structure-dependent effects.

    ↳ nucl-thnucl-ex0 citations
  5. 05

    A Differential Neutral-to-Charged Current Double-Proton Observable for Studying Short-Range Correlations in Neutrino--Argon Scattering

    A. Bueno🇪🇸 · D. Garcia-Gamez🇪🇸 · C. Martin-Morales🇪🇸

    Two-nucleon emission is a leading uncertainty in neutrino--nucleus interaction modeling, and no neutrino measurement constrains its short-range-correlation (SRC) component. We propose such a measurement: the ratio of neutral-current to charged-current two-proton production in neutrino--argon interactions as a function of the proton-pair relative momentum. Charged-current interactions convert the abundant neutron--proton SRC pairs into visible proton pairs, whereas neutral-current interactions lack an analogous SRC contribution because proton--proton pairs are about twenty times less abundant. The ratio is therefore predicted to decrease at large relative momentum, where the charged-current SRC contribution dominates, while the neutral-current sample provides a smooth reference determined mainly by final-state interactions and multinucleon processes. Simulations predict a suppression whose magnitude scales with the SRC fraction. Flux normalization and correlated detector systematics largely cancel in the ratio, making the measurement feasible with existing liquid-argon time projection chambers. Independently of the precise SRC contribution, this observable provides the first direct experimental probe of the isospin structure of weak two-nucleon emission.

    ↳ hep-exnucl-ex0 citations
  6. 06

    Relativistic corrections and high-energy resummation for exclusive heavy quarkonium photoproduction

    Maxim Nefedov🇮🇱

    The correction to the high-energy resummed coefficient function for the exclusive photoproduction of vector () heavy quarkonia off hadrons is computed, thereby taking into account corrections of . When expressed in terms of the physical vector-meson mass () and the relative heavy-quark velocity () using the Gremm-Kapustin relation, the computed correction turns out to be negligible at the scale . However, it partially cancels the dependence of the correction to the LO coefficient function in , thereby improving the robustness of the predictions.

    ↳ hep-phhep-exnucl-exnucl-th0 citations
  7. 07

    Radiative corrections in neutral-current (anti)neutrino elastic scattering at energies I: Nucleon targets

    Yi Chen🇨🇳 · Oleksandr Tomalak🇨🇳 · Bing-Song Zou🇨🇳

    We introduce radiative corrections in neutral-current (anti)neutrino-nucleon elastic scattering at energies within the effective field theory framework. We factorize cross sections into soft and hard functions, clarify the (anti)neutrino flavor dependence at both amplitude and cross-section levels, and improve the quantum chromodynamics (QCD) contributions to low-energy neutral-current processes. The radiative corrections at the single-nucleon level reach a magnitude comparable to the contributions from strange quarks. We also compare our results with the experimental data from BNL E734 and MiniBooNE collaborations, finding excellent agreements with the experimental data.

    ↳ hep-phhep-exhep-latnucl-ex+10 citations

Affiliations

first authorsco-authorsvia INSPIRE