PaperPanorama

Nuclear Experiment·nucl-ex

Wed·Sep 2, 2026

5 papers—0 primary·5 cross-listed

All5Primary0Cross-lists5
  1. 01

    Equation of state and neutron star properties with new mass-radius constraints from PSR~J1614--2230, PSR~J2124--3358, and 47~Tuc~X7

    Melissa Mendes🇩🇪 · Isak Svensson🇩🇪 · Hannah Gottling🇩🇪 · Kai Hebeler🇩🇪 · Achim Schwenk🇩🇪 · Nathan Rutherford🇺🇸 · Lucien Mauviard🇫🇷 · Christine Kazantsev🇫🇷 · Yves Kini🇳🇱 · Denis Gonzalez-Caniulef🇫🇷 · Sebastien Guillot🇫🇷 · Anna Watts🇳🇱

    We study the impact of new mass-radius information from PSR J1614-2230, PSR J2124-3358, and 47 Tuc X7 in a combined equation of state inference based on chiral effective field theory constraints at nuclear densities and using different high-density extensions, including perturbative QCD constraints. The largest impact stems from the heavy-mass PSR J1614-2230 star, which shifts heavy neutron stars to smaller radii by around 0.4 km. Moreover, the combined astrophysical NICER, LIGO/Virgo, and X-ray information drives the radius posterior to a more data-driven distribution, which is less sensitive to the high-density extension. For the equation of state, the new mass-radius information significantly tightens the pressure and speed-of-sound posterior distributions, especially around three times saturation density. Finally, we make predictions for the poorly constrained masses of PSR J2124-3358 and 47 Tuc X7 based on the combined equation of state analysis and the other astrophysical sources.

    ↳ astro-ph.HEnucl-exnucl-th0 citations
  2. 02

    Saturation effects in diffractive deep inelastic scattering

    Jani Penttala🇺🇸 · Christophe Royon🇺🇸 · Jarno Vierros🇺🇸

    We study the production of and quarks in photon-induced processes as a probe of gluon saturation, with a focus on the high-energy region accessible in ultra-peripheral collisions (UPCs) at the LHC. We compare predictions for inclusive and diffractive heavy quark production with and without saturation effects by using the nonlinear Balitsky--Kovchegov and the linear Balitsky--Fadin--Kuraev--Lipatov equations for the evolution of the dipole amplitude. The percentage of coherent diffractive events is predicted to be in the saturation model, which is approximately twice as large as predictions based on parton distribution functions and shadowing. This indicates that measurements of diffractive heavy quark production in UPCs may provide a sensitive probe for distinguishing linear and nonlinear regimes of quantum chromodynamics.

    ↳ hep-phhep-exhep-thnucl-ex+10 citations
  3. 03

    QED nuclear medium effects at EicC

    Oleksandr Tomalak🇨🇳

    We evaluate quantum electrodynamics (QED) nuclear medium effects under experimental conditions at the future Electron-ion collider in China (EicC). We consider neutral-current and charged-current elastic scattering, as well as neutral-current and charged-current deep inelastic scattering. We compute cross-section corrections at first order in the opacity expansion and estimate kinematic modifications due to multiple rescattering within the nucleus. We perform the first calculations of charged-current deep inelastic scattering and polarized scattering. We present results for the anticipated and nuclei and extrapolate these calculations to the lighter isotope. We find that QED nuclear medium effects are non-negligible when extracting the process-independent non-perturbative structure of nucleons and nuclei at the EicC.

    ↳ nucl-thhep-exhep-phnucl-ex0 citations
  4. 04

    Fundamental geometric limitations on disentangling nuclear-surface properties in relativistic heavy ion collisions

    Hadi Mehrabpour🇨🇳 · Behnaz Behzadmoghaddam🇮🇷 · S. M. A. Tabatabaee Mehr🇮🇷 · Oscar Garcia-Montero🇪🇸 · Li Yan🇨🇳

    The extraction of the nuclear surface diffuseness from relativistic heavy ion collisions is limited by the intertwined responses of geometry-driven observables to surface diffuseness and intrinsic nuclear deformation. We investigate this limitation using event-by-event Monte Carlo Glauber simulations, focusing on the sensitivity of multiparticle correlations to the Woods--Saxon surface diffuseness in intrinsically deformed nuclei. We systematically examine the local correlations between and quadrupole and octupole deformation parameters, and , and determine how these correlations affect the ability of different observables to constrain . We find that observables dominated by elliptic geometry exhibit a strong response to quadrupole deformation, leading to a local -- degeneracy that substantially limits their sensitivity to the nuclear surface diffuseness. Triangular correlations provide a more independent response to the nuclear surface and therefore retain additional information on , although their sensitivity can also be modified by intrinsic deformation. Extending the analysis to simultaneous quadrupole and octupole deformation shows that the local degeneracy and least-constrained directions depend on the nuclear configuration, demonstrating that the limitation on extracting is not described by a single global parameter correlation. We quantify these effects using multidimensional response maps, local sensitivity and information-geometric measures, and a Bayesian analysis of the resulting parameter constraints. The results clarify the fundamental limitations imposed by intrinsic multipole deformation on the determination of nuclear surface diffuseness from relativistic heavy ion collisions and identify multiparticle correlations that provide more independent information on .

    ↳ nucl-thhep-exhep-phnucl-ex0 citations
  5. 05

    Validating a BDT-based Electron-Positron Identification Algorithm at CLAS12 with Experimental Data

    Mariana Tenorio Pita🇺🇸 · Pierre Chatagnon🇫🇷 · Richard Tyson🇬🇧

    This article presents a machine-learning, particle-identification algorithm for electrons and positrons in the CLAS12 experiment. The main objective was to minimize charged-pion contamination for both experimental and simulated data. We developed, evaluated and validated two BDT models with different input features, both trained on simulated samples, and conducted rigorous validation using both simulated and experimental data to ensure reliability. Our results show the effectiveness of the applied models in mitigating background contamination. By retaining more than 90\% of leptons in the simulated samples, the charged-pion background is largely reduced. Performance was evaluated on experimental data, providing a framework to validate such approaches at CLAS12 and future electron-beam facilities.

    ↳ hep-exnucl-exphysics.ins-det0 citations

Affiliations

first authorsco-authorsvia INSPIRE