Tue·Oct 28, 2025Tuesday·October 28, 2025

1. 01*

   Threshold $J/\psi$ Photoproduction as a Probe of Nuclear Gluon Structure

   J. R. Pybus · D. Dutta · H. Gao · O. Hen · I. Korover · T. Kolar · A. Schmidt · A. Somov · H. Szumila-Vance · D. Androić · C. Ayerbe Gayoso · X. Bai and 75 other authors

   The nuclear EMC effect is the observation that quark distributions in bound nucleons experience significant modification at large $x$ relative to free nucleons. Despite decades of measurements verifying the presence of this effect in quarks across a wide range of nuclei, behavior of large-$x$ gluons in nuclei remains almost completely unknown. As the nuclear physics community seeks out new observables to try to elucidate the mechanisms behind the EMC effect, it becomes striking that we remain ignorant regarding the impact of nuclear effects on gluonic behavior. Recent photonuclear data using the Hall D photon beam have enabled the first measurement of $J/\psi$ photoproduction from nuclei near and below the energy threshold, with the results highlighted in Physical Review Letters as an Editors' Suggestion. These data have placed the first, and currently only, constraints on the behavior of large-$x$ gluons within bound nucleons. However, compared to the quantity of data which currently informs our knowledge of the quark-sector EMC effect, these data are extremely limited, and remain unable to conclusively observe or exclude large modification of gluon distributions. A high-luminosity photonuclear experiment will enable a precision measurement of incoherent $J/\psi$ photoproduction at and below the threshold region. This data will provide the first stringent constraints on nuclear modification of gluon structure or other exotic effects which could impact the production of $J/\psi$ from nuclei. We request 85 PAC days at Hall D using the GlueX detector with a 12 GeV electron beam energy and a coherent photon peak energy of $8$ GeV, split into 80 days using a ${}^4$He target and 5 calibration days using a ${}^2$H target.

   nucl-ex4 citations
2. 02*

   The Roper resonance and kin

   Volker Burkert🇺🇸 · Eberhard Klempt🇩🇪

   The properties of the Roper resonance N(1440) are reviewed. Quark models have long struggled to reproduce its mass relative to its negative-parity partner N(1535). This discrepancy motivated interpretations of the Roper as a dynamically generated meson-baryon state. Including its isospin partners Delta(1600) and Delta(1700) further accentuates the tension between quark-model predictions and experiment. Recent developments based on AdS/QCD and functional methods achieve much improved agreement, identifying the Roper as an ordinary three-quark excitation. Electroproduction experiments at Jefferson Lab have now resolved this long-standing question, revealing the Roper as a qqq core dressed by a substantial meson cloud. The Roper resonance belongs to a family of four N* states with JP = 1/2+; the highest-mass member, N(2100), likely represents a Roper-like excitation in the fourth shell.

   nucl-exActa Phys.Polon.B(2026)·2 citations
3. 03*

   Neutron capture measurement of the 165Ho at the CSNS Backn facility in the resonance energy region

   De-Xin Wang · Su-Ya-La-Tu Zhang🇨🇳 · Wei Jiang🇨🇳 · Rui-Rui Fan🇨🇳 · Qi-Wei Zhang🇨🇳 · Jie Ren🇨🇳 · Jin-Cheng Wang🇨🇳 · Guang-Yuan Luan · Xiao-Guang Wu · Bao-Hua Sun · Zhen-Xiang Zhou · Hong-Yi Wu and 8 other authors

   The neutron capture yield of 165Ho have been measured at the Back-streaming White neutron beam line (Back-n) of the China Spallation Neutron Source (CSNS) using a 4{\pi} BaF2 Gamma Total Absorption Facility (GTAF). The resonance shapes in the 1eV to 1.0keV region were analyzed with the Bayesian R-matrix code SAMMY. For 18 s-wave resonances below 100eV, the resonance energy ER, neutron width {\Gamma}n, and radiative width {\Gamma}{\gamma} were extracted. The statistical analyses of the resonance parameters show that the nearest-neighbour level-spacing distribution follows a Wigner-Dyson form with mean spacing D0 = 4.53(3)eV,indicating chaotic compound-nucleus behaviour; Using the extracted parameters, the s-wave neutron strength function for 165Ho was derived to be 10-4S0 = 2.01(1), in excellent agreement with the values reported in both the Atlas of Neutron Resonances and ENDF/B-VIII.0 data.

   nucl-exphysics.ins-det0 citations
4. 04*

   Using the Neutron Fizeau Effect and Neutron Interferometry to Measure Energy-Dependent Contributions to the Neutron Optical Potential

   W. M. Snow🇺🇸 · V. Kurmangaliyeva🇰🇿 · O. Agyl-Mussapar · S. Amangeldinova🇰🇿 · B. Massak · D. Nassirova · V. Zhumabekova

   We propose a method to measure the energy dependence of the neutron optical potential $d{V}_{opt}/dE$ in the slow neutron energy regime. Our method makes essential use of a special property of the phase shift for a nonrelativistic neutron in moving matter, known as the neutron Fizeau effect. If a neutron traverses a medium which moves along the surfaces of its own parallel boundaries, the neutron only experiences a phase shift if the neutron optical potential of matter depends on the incident neutron energy. This feature of the neutron Fizeau effect can be combined with newly-developed forms of neutron interferometry to conduct sensitive measurements of $d{V}_{opt}/dE$. We describe some examples of scientific applications of this idea in the fields of neutron optics, subthreshold neutron-nucleus resonances, parity violation in low-energy p-wave neutron-nucleus resonances, and neutron scattering amplitudes of the nuclei of rare earth elements.

   nucl-ex0 citations
5. 05*

   New Hypernuclei Measurements from STAR

   Yingjie Zhou (for the STAR Collaboration)🇩🇪

   Hypernuclei are bound states of hyperons (Y) and nucleons (N). Measurements on their yields can help us investigate their production mechanisms. In particular, the ${}_{\Lambda }^5$He and ${}_{\Lambda }^4$H(e) are substantially tighter bound compared to the ${}_{\Lambda }^3$H. The large radius of the ${}_{\Lambda }^3$H leads to suppression in coalescence models, but not in the thermal model where the size of the nucleus does not play a role. As such, studying the $A=3$--5 hypernuclei yields allow us to extract information on the effects of hypernuclear binding on hypernuclei production in heavy-ion collisions. In these proceedings, we present measurements of ${}_{\Lambda }^5$He yields in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=3.0$ GeV, ${}_{\Lambda }^4$H(e) yields in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=3.0$--$4.5$ GeV, and ${}_{\Lambda }^3$H yields in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=3$--$27$ GeV. Results on the directed flow of hypernuclei are also reported. The physics implications of these measurements are discussed.

   nucl-exhep-exEPJ Web Conf.(2026)·1 citation
6. 06*

   Determination of the Muon Lifetime in ${}^{76}$Se with the MONUMENT experiment

   G. R. Araujo🇨🇭 · D. Bajpai🇺🇸 · L. Baudis🇨🇭 · V. Belov🇷🇺 · E. Bossio🇩🇪 · T.E. Cocolios🇧🇪 · H. Ejiri🇯🇵 · M. Fomina🇷🇺 · K. Gusev🇷🇺 · I.H. Hashim🇲🇾 · M. Heines🇧🇪 · S. Kazartsev🇷🇺 and 17 other authors

   Ordinary muon capture provides a benchmark for the nuclear physics models of neutrinoless double beta decay under comparable momentum transfer conditions. The total capture strength defines the lifetime of the muonic atom. The muon lifetime in ${}^{76}$Se, the daughter nucleus of ${}^{76}$Ge, was determined with improved accuracy by the MONUMENT collaboration, using an array of high-purity germanium detectors and a set of scintillator counters at the $\pi$E1 muon beam line of the Paul Scherrer Institute. The new value of (135.1 $\pm$ 0.5) ns agrees with phenomenological calculations based on the quasiparticle random phase approximation with unquenched axial-vector coupling.

   nucl-exnucl-thPRC(2026)·0 citations
7. 07*

   Robust and Generalizable Background Subtraction on Images of Calorimeter Jets using Unsupervised Generative Learning

   Yeonju Go🇺🇸 · Dmitrii Torbunov🇺🇸 · Yi Huang🇺🇸 · Shuhang Li🇺🇸 · Timothy Rinn🇺🇸 · Haiwang Yu🇺🇸 · Brett Viren🇺🇸 · Meifeng Lin🇺🇸 · Yihui Ren🇨🇳 · Dennis Perepelitsa🇺🇸 · Jin Huang🇺🇸

   Accurate separation of signal from background is one of the main challenges for precision measurements across high-energy and nuclear physics. Conventional supervised learning methods are insufficient here because the required paired signal and background examples are impossible to acquire in real experiments. Here, we introduce an unsupervised unpaired image-to-image translation neural network that learns to separate the signal and background from the input experimental data using cycle-consistency principles. We demonstrate the efficacy of this approach using images composed of simulated calorimeter data from the sPHENIX experiment, where physics signals (jets) are immersed in the extremely dense and fluctuating heavy-ion collision environment. Our method outperforms conventional subtraction algorithms in fidelity and overcomes the limitations of supervised methods. Furthermore, we evaluated the model's robustness in an out-of-distribution test scenario designed to emulate modified jets as in real experimental data. The model, trained on a simpler dataset, maintained its high fidelity on a more realistic, highly modified jet signal. This work represents the first use of unsupervised unpaired generative models for full detector jet background subtraction and offers a path for novel applications in real experimental data, enabling high-precision analyses across a wide range of imaging-based experiments.

   nucl-exphysics.data-anGo, Y., Torbunov, D., Huang, Y. et al. Ro…·1 citation
8. 08*

   Pairing gap as a new observable for critical points in the region of A=100

   Hossein Emami · Hadi Sabri

   This study used the pairing gap to identify nuclei as candidates for critical point symmetry around Z=40 and A=100. Nuclei around A = 100 display complex shape evolution and configuration crossing patterns. We utilized the experimental and algebraic frameworks of the interacting boson model and the newly developed interacting boson-fermion model to study the isotopes of Mo and Ru. The results show significant variations in these quantities across nuclei located at the E(5) and X(5) critical points, analyzed through different observables. We also examined another region that is suitable for a shape phase transition. Furthermore, our findings suggest new candidates for critical points in other phase transitional regions for different isotopic chains.

   ↳ nucl-thnucl-exMod.Phys.Lett.A(2026)·0 citations
9. 09*

   Origin of the electric hexadecapole isomer in ${}^{93}$Mo

   B. Maheshwari🇫🇷 · P. Van Isacker🇫🇷 · P. M. Walker🇬🇧

   We present a shell-model analysis of ${}^{93}$Mo to investigate the unusual behavior of its ${21/2}^{+}$ isomer -- a prominent candidate for nuclear excitation by electronic capture. This state is unique as its decay is dominated by a slow electric hexadecapole $E4$ transition, while the typically much faster electric quadrupole $E2$ decay path is energetically forbidden. We investigate the microscopic origin of this phenomenon by examining in detail the structure of the wave functions of the initial and final states, and the $E4$ transition matrix elements. This analysis of ${}^{93}$Mo is contrasted with that of its particle-hole conjugate, ${}^{99}$Cd, where such an $E4$ transition is absent.

   ↳ nucl-thnucl-exEPJ Web Conf.(2025)·0 citations
10. 10*

    Heavy-Flavor Fragmentation and Jet Structure from HF-NRevo: Bridging to Heavy-Ion Collisions

    Francesco Giovanni Celiberto🇪🇸 · Francesca Lonigro🇪🇸

    We present recent progress on the Heavy-Flavor Non-Relativistic Evolution (HF-NRevo) framework, designed to describe leading-power fragmentation of heavy-flavored hadrons at moderate to large transverse momentum. Starting from NLO NRQCD calculations for all partonic channels into pseudoscalar quarkonia, we construct the NRFF1.0 collinear fragmentation functions via DGLAP evolution in a variable-flavor number scheme. We outline future prospects in the heavy-ion context, where HF-NRevo can serve as a baseline for modeling in-medium modifications of heavy-flavor fragmentation in nuclear collisions. Its accurate modeling of the partonic hierarchy and threshold effects makes it ideally suited to explore jet-quenching sensitivity, energy-loss mechanisms, and the emergence of medium-modified fragmentation functions in the quark-gluon plasma. Moreover, it provides a natural baseline for implementing in-medium hadronization scenarios, including quarkonium regeneration and fragmentation-function apparent-shape distortion. These developments provide new handles for exploring heavy-flavor dynamics at the HL-LHC and future collider facilities.

    ↳ hep-phhep-exhep-thnucl-ex+1PoS(2026)·10 citations
11. 11*

    An End-to-End Generative Diffusion Model for Heavy-Ion Collisions

    Jing-An Sun🇨🇳 · Li Yan🇨🇳 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦

    Heavy-ion collision physics has entered the high precision era, demanding theoretical models capable of generating huge statistics to compare with experimental data. However, traditional hybrid models, which combine hydrodynamics and hadronic transport, are computationally intensive, creating a significant bottleneck. In this work, we introduce DiffHIC, an end-to-end generative diffusion model, to emulate ultra-relativistic heavy-ion collisions. The model takes initial entropy density profiles and transport coefficients as input and directly generates two-dimensional final-state particle spectra. Our results demonstrate that DiffHIC achieves a computational speedup of approximately $10^5$ against traditional simulations, while accurately reproducing a wide range of physical observables, including integrated and differential anisotropic flow, multi-particle correlations, and momentum fluctuations. This framework provides a powerful and efficient tool for phenomenological studies in the high-precision era of heavy-ion physics.

    ↳ nucl-thnucl-exEPJ Web Conf.(2026)·0 citations
12. 12*

    Non-local orbital-free density functional theory incorporating nuclear shell effects

    Xinhui Wu · Gianluca Colò🇮🇹 · Kouichi Hagino🇯🇵 · Pengwei Zhao🇨🇳

    Incorporating nuclear shell effects within the framework of orbital-free density functional theory (DFT) has remained a longstanding challenge in nuclear physics. While the Hohenberg-Kohn theorem formally guarantees the existence of an orbital-free density functional that is capable of describing all many-body effects, including shell effects, practical attempts since the 1970s have consistently failed to capture such effects. This persistent difficulty has even led to the misconception that the orbital-free DFT is inherently unable to describe nuclear shell effects. Here we develop a {\it non-local} orbital-free DFT approach for atomic nuclei and demonstrate that nuclear shell effects can be successfully incorporated into the orbital-free DFT through the construction of a non-local kinetic energy density functional. In particular, we show that the non-local orbital-free functional yields a nucleon localization function that, as an established indicator of shell effects, exhibits consistent behavior with the exact Kohn-Sham solution.

    ↳ nucl-thnucl-exPRL(2026)·5 citations
13. 13*

    Krisenmanagement in Kerntechnischen Notfällen -- Eine Evaluaierung Am Beispiel der Nuklearkatastrophe von Fukushima

    Elias Koschier

    The objective of this pre-scientific paper is to analyze the crisis management during the Fukushima nuclear accident in the year of 2011 and to derive lessons for a safer operation of reactors along with a more resilient crisis management framework. In addition to official reports and subject literature, the conducted methods included interviews with an IAEA safeguard and a political scientist. The central findings were that the accident pointed out deficiencies regarding the independence of the regulatory body and that mismanagement of the available technical resources in conjunction with insufficient communication led to evitable evacuations.

    ↳ physics.hist-phnucl-ex0 citations
14. 14*

    Emergent spin polarization from $\rho$ meson condensation in rotating hadronic matter

    Kshitish Kumar Pradhan🇮🇳 · Dushmanta Sahu🇲🇽 · Raghunath Sahoo🇮🇳

    The behavior of vector mesons in extreme environments provides a unique probe of non-perturbative Quantum Chromodynamics. We investigate the conditions for Bose-Einstein condensation (BEC) of spin-1 $\rho$ mesons in dense rotating hadronic matter, a regime relevant to the peripheral heavy-ion collisions and the interiors of rapidly rotating neutron stars. When the $\rho$ meson chemical potential (${\mu }_{\rho }$) approaches its effective mass ($m_{\rho }^{\ast }$), a phase transition to BEC occurs. We demonstrate that this transition is non-trivially influenced by global rotation, which couples to the spin of the $\rho$ mesons, leading to a macroscopic spin alignment of the condensate along the axis of rotation. This interplay between condensation and rotation results in distinct polarization patterns, which can serve as a possible signature of a BEC in experiments. The results suggest that rapidly rotating neutron stars may harbor an anisotropic, spin-polarized $\rho$-condensed phase, which could impact their equation of state.

    ↳ hep-phhep-exhep-thnucl-ex+1PLB(2026)·3 citations
15. 15*

    Baryon and electric charge stoppings in nuclear collisions and the role of strangeness

    Mason Alexander Ross🇺🇸 · Zi-Wei Lin🇺🇸

    It has been challenging to quantitatively understand the stopping of incoming nucleons in nuclear collisions, and recently it has been proposed that comparing the baryon stopping with electric charge stopping can help address the question. Here we focus on the $B/Q\times Z/A$ ratio, which can strongly depend on rapidity although its value is one for the full phase space. We find that this ratio is very sensitive to the difference between strange and anti-strange rapidity distributions (the $s-\bar{s}$ asymmetry), and slightly more anti-strange quarks at mid-rapidity would lead to a ratio well below one. This is the case for Zr+Zr and Ru+Ru isobar collisions at $200A$ GeV from a multi-phase transport (AMPT) model. Without the $s-\bar{s}$ asymmetry, the AMPT model would give a mid-rapidity $B/Q\times Z/A$ ratio at or above one. In addition, the AMPT model gives $B/\Delta Q\times \Delta Z/A<1$ at mid-rapidity for isobar collisions at all centralities, which strongly contradicts the recent data from the STAR Collaboration. We further find that the $B/\Delta Q\times \Delta Z/A$ ratio is very sensitive to the net-light quark ($u,d$) stoppings, but it is less sensitive to the $s-\bar{s}$ asymmetry than the $B/Q\times Z/A$ ratio by a factor of 3.

    ↳ nucl-thhep-phnucl-exEPJC(2026)·4 citations
16. 16*

    Search for dark matter Particles via Invisible Decays in ${}^{46}$Sc Nuclear $\gamma$ Cascades with a CsI(Tl) Detector

    Sharada Sahoo🇺🇸 · Jing-han Chen🇨🇳 · Mahdi Mirzakhani🇺🇸 · Harikrishnan Ramani🇺🇸 · Rupak Mahapatra🇺🇸 · Surjeet Rajendran🇺🇸

    Dark matter remains one of the most compelling open problems in modern physics, motivating experimental searches for new light, weakly coupled particles beyond the Standard Model. Despite extensive efforts employing diverse detection strategies, large regions of parameter space remain unexplored. We report a high-statistics laboratory search for invisible decay modes in nuclear $\gamma$-ray cascades using approximately $100\mathrm{kg}$ of CsI(Tl) scintillators operated at Texas A\&M University. The experiment employs a high-activity ${}^{46}$Sc radioactive source and a ``missing-$\gamma$'' technique, in which the absence of a photon from a well-identified cascade serves as a signature of new physics. Unlike appearance-disappearance experiments, this approach requires only a single photon conversion into a dark-sector particle, enabling sensitivity to significantly weaker couplings. The setup provides simultaneous sensitivity to a broad class of light dark-sector candidates, including axions and axion-like particles, dark scalars, and dark photons in the $0.1-1\text{ MeV}$ mass region. Through careful control of detector containment, energy resolution, and environmental backgrounds, we exclude certain regions on the previously explored parameter space. With foreseeable improvements in detector volume and systematic uncertainty control, this technique has the potential to probe currently unexplored parameter space for axion-like particles and light dark scalars.

    ↳ physics.ins-detnucl-ex0 citations
17. 17*

    Calculation of Particle Pair Correlation Functions with Classical Trajectory Approximation

    Sheng Xiao🇨🇳 · Yijie Wang🇨🇳 · Zhigang Xiao

    Femtoscopic interferometry is a powerful tool for probing the spatio-temporal evolution of emission sources in heavy-ion collisions. A major challenge in the field is formulating a self-consistent description of the source function, final-state interactions between the particle pair, and interactions inherent to the source itself. To address this, we have developed a novel Monte Carlo model for calculating two-particle correlation functions in a classical trajectory approximation (CTA-I). The model incorporates self-consistently the emission source of thermal equilibrium and three-body final state interactions. Application of the model shows satisfactory fit to experimental data, revealing that the correlation function is highly sensitive to the source's spatio-temporal extent. In contrast, the temperature parameter governing the emitted particles' energy spectra has a negligible influence. Our approach offers the potential to extract the spatio-temporal information from the emission source, thereby advancing the applicability of femtoscopic interferometry in the Fermi energy domain.

    ↳ nucl-thnucl-ex0 citations
18. 18*

    New Bounds on Heavy QCD Axions from Big Bang Nucleosynthesis

    Tae Hyun Jung🇰🇷 · Takemichi Okui🇺🇸 · Kohsaku Tobioka🇺🇸 · Jiabao Wang🇺🇸

    We study Big Bang Nucleosynthesis (BBN) constraints on heavy QCD axions. BBN offers a powerful probe of new physics that modifies the neutron-to-proton ratio during the process, thanks to the precisely measured primordial Helium-4 abundance. A heavy QCD axion provides an attractive target for this probe, because not only is it a well-motivated hypothetical particle by the strong CP problem, but also it dominantly decays to hadrons if kinematically allowed. A range of its lifetime is thus excluded where the hadronic decays would significantly alter the neutron-to-proton ratio. We compute axion-induced modification of the neutron-to-proton ratio, and obtain robust upper bounds on the axion lifetimes, as low as 0.017 s for the axion mass higher than 300 MeV. Remarkably, this is stronger than projected future CMB bounds via $N_{\mathrm{eff}}$. Our bounds are largely insensitive to uncertainties in hadronic cross sections and the axion's branching fractions into various hadrons, as well as to the precise value of the initial axion abundance. We also incorporate, for the first time, several key improvements, such as scattering processes by energetic $K_L$ and secondary hadrons, that can also be important for studying general hadronic injections during BBN, not limited to those from axion decays.

    ↳ hep-phastro-ph.COhep-exnucl-exPRD(2026)·9 citations
19. 19*

    Towards a comprehensive study of the 14N(p,g)15O astrophysical key reaction: Description of the experimental technique including novel target preparation

    A. Compagnucci · A. Formicola🇮🇹 · M. Campostrini · J. Cruz · M. Aliotta🇬🇧 · C. Ananna🇮🇹 · L. Barbieri · F. Barile · D. Bemmerer🇩🇪 · A. Best🇮🇹 · A. Boeltzig🇩🇪 · C. Broggini🇮🇹 and 37 other authors

    While the 14N(p,g)15O reaction plays a key role in the hydrogen-burning processes in various stellar conditions, its reaction rate is not known with sufficient precision. Therefore, the first scientific project at the recently launched Bellotti Ion Beam Facility of the Laboratori Nazionali del Gran Sasso was the measurement of the 14N(p,g)15O reaction cross section in the proton energy range between 250 and 1500 keV. In this paper, the experimental techniques are summarized with special emphasis on the description of solid state nitrogen target production and characterization. The first results of the reaction yield measured at 55 deg detection angle are also presented.

    ↳ physics.ins-detastro-ph.SRnucl-exEPJA(2025)·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.