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Nuclear Theory·nucl-th

Friday·October 18, 2024

17 papers—7 primary·10 cross-listed

All17Primary7Cross-lists10
  1. 01

    An end-to-end generative diffusion model for heavy-ion collisions

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

    We train a generative diffusion model (DM) to simulate ultra-relativistic heavy-ion collisions from end to end. The model takes initial entropy density profiles as input and produces two-dimensional final particle spectra, successfully reproducing integrated and differential observables. It also captures higher-order fluctuations and correlations. These findings suggest that the generative model has successfully learned the complex relationship between initial conditions and final particle spectra for various shear viscosities, as well as the fluctuations introduced during initial entropy production and hadronization stages, providing an efficient framework for resource-intensive physical goals. The code and trained model are available at https://huggingface.co/Jing-An/DiffHIC/tree/main.

    nucl-thhep-phnucl-exPRC(2025)·10 citations
  2. 02

    Azimuthal Correlation Anisotropies in p + p Collisions Simulated by Pythia

    Manuel Sebastian Torres🇨🇴 · Yicheng Feng🇺🇸 · Fuqiang Wang🇺🇸

    Stimulated by the keen interest of possible collective behavior in high-energy proton-proton and proton-nucleus collisions, we study two-particle angular correlations in pseudorapidity and azimuthal differences in simulated p + p interactions by the Pythia 8 event generator. Multi-parton interactions and color connection are included in these simulations which have been perceived to produce collectivity in final-state particles. Meanwhile, contributions from genuine few-body nonflow correlations, not of collective flow behavior, are known to be severe in those small-system collisions. We present our Pythia correlation studies in a pedagogical way and report azimuthal harmonic anisotropies analyzed by several methods. We observe anisotropies in those Pythia simulated events qualitatively and semi-quantitatively similar to experimental data. Our findings highlight the delicate nature of azimuthal anisotropies in small-system collisions, and provide a benchmark helping improve data analysis and interpret experimental measurements in small-system collisions.

    nucl-thnucl-exCPC(2025)·1 citation
  3. 03

    Systematics of supernumerary nuclear rainbow in inelastic O+C scattering

    Nguyen Hoang Phuc · Nguyen Tri Toan Phuc · Do Cong Cuong

    We perform a systematic study of inelastic nuclear rainbow scattering for the \oc system to the 2 (4.44 MeV) state of C at incident energies of 100--608 MeV with the coupled-channels method. The recently generalized nearside-farside decomposition for inelastic scattering was applied in combination with the multichannel deflection function analysis to elucidate the origin of the nuclear rainbow phenomenon and the suppression of the primary and supernumerary Airy minima in the inelastic scattering cross section. The systematic evolution of the Airy minima for the excited 2 (4.44 MeV) state of C was unambiguously determined. Our work suggests that there is no clear shift in the positions of the first Airy minima and a small shift at low energies for the second and third Airy minima between the inelastic and elastic scattering cross sections. Using the -subamplitudes splitting technique combined with the generalized nearside-farside decomposition and deflection function, the distinct refractive pattern commonly suppressed in the inelastic heavy-ion scattering can be interpreted and provides new insights into the relationship between elastic and inelastic nuclear rainbow scattering.

    nucl-thPRC(2024)·0 citations
  4. 04

    Impact parameter dependence of the effect of background field on coupling constant in heavy ion collisions

    Cong Li🇨🇳

    We investigated the impact parameter dependence of the background field's effect on the coupling constant of the process in heavy-ion collisions. The peripheral electric fields of heavy ions collide, and after photon annihilation into lepton pairs, the subsequent emission of radiation photons will be affected by the background field. Numerical estimates indicate that the dependence of this effect on the impact parameter is significant during this process.

    nucl-thhep-ph0 citations
  5. 05

    Negative moments as the signature of the radial density at small distances

    M. Atoui🇫🇷 · M. Hoballah🇫🇷 · M. Lassaut🇫🇷 · J. Van de Wiele🇫🇷

    The present paper proposes a robust evaluation of any radial density at small distances using negative-order radial moments evaluated in momentum space. This evaluation provides a valuable insight into the behavior of a given radial density in the vicinity of , and puts strong emphasis on the importance of measuring form factors at large squared four-momentum transfer, a domain essential for the determination of negative order moments. A specific attention is paid to the regularization scheme directly affecting the numerical determination of the radial density's parametrization. The proposed method is applied to non-relativistic study cases of the nucleon electric (), and proton magnetic form factors. The validation is performed through comparison of the results of the approach to the analytically determined Maclaurin expansion - in the vicinity of - of the radial density function. The method is also applied to the relativistic Dirac form factor of the proton. In such a non-trivial case, the Maclaurin development might not exist for the radial density, rendering the determination from the proposed method extremely important.

    nucl-thnucl-exEPJA(2025)·0 citations
  6. 06

    Microscopic description of spontaneous fission based on a Gogny energy density functional including tensor contributions

    R. Rodríguez-Guzmán🇰🇿 · L.M. Robledo🇪🇸 · R.N. Bernard🇫🇷

    This paper extends previous studies on the impact of tensor forces in fission dynamics of neutron-deficient Thorium isotopes to other isotopic chains of heavy actinides and low-mass super-heavy nuclei. Calculations are carried out within a mean-field framework based on the Gogny-D1S parametrization supplemented with the D1ST2a perturbative tensor term as driving force. Fission barrier heights and spontaneous fission half-lives are used as benchmarks to analyze the impact of the tensor term. A significant reduction of fission barrier heights and half-lives is associated to the tensor component of the force.

    nucl-thJ.Phys.G(2024)·5 citations
  7. 07

    Neutron-neutron distribution of the triton from pionless EFT

    Tanja Kirchner · Matthias Göbel · Hans-Werner Hammer

    We compute the neutron-neutron relative-energy distribution of the triton following the hard knockout of the proton in pionless effective field theory. This distribution can be used to study universality as well as to obtain information on the neutron-neutron interaction. Especially, one can infer the scattering length from fitting theory predictions for the shape of the distribution to experimental data. To obtain the distribution for the triton, we first solve the ground-state three-body problem using momentum-space Faddeev equations. Next, we include the neutron-neutron final-state interaction by applying the corresponding Møller operator to the ground state. We present leading-order (LO) and next-to-leading order (NLO) pionless effective field theory results with quantified uncertainties. At NLO, we include the effective ranges semi-perturbatively. We conclude, that pionless EFT works reliably as expected and that the neutron-neutron distribution of the triton shows a significant sensitivity to the scattering length.

    nucl-thnucl-exPRC(2025)·1 citation

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first authorsco-authorsvia INSPIRE