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Nuclear Theory·nucl-th

Thursday·April 10, 2025

7 papers—6 primary·1 cross-listed

All7Primary6Cross-lists1
  1. 01

    Non Nucleonic Components in Short Nuclear Distances

    Misak M Sargsian

    One of the important features of nuclear forces is their strong repulsive nature at short (~Fm) distances which prevents atomic nuclei from collapsing, thus guarantying the stability for the visible matter. However the dynamical nature of this repulsion (referred to as a nuclear core) is as elusive as ever. We present the study of nuclear dynamics at extremely large internal momenta in the deuteron dominated by the nuclear core. It is demonstrated that the paradigm shift in the description of the deuteron consisting of proton and neutron to the description of the deuteron as a pseudo-vector composite system in which proton and neutron is observed in high energy electro-disintegration processes results in the emergence of a new structure. We demonstrate that this new structure can exist only if it emerges from pre-existing non-nucleonic component in the deuteron. The study of the dynamics of the predicted new structure is presented focusing on the question if it allows to understand the anomaly observed in the recent experiment at Jefferson Lab that probed deuteron structure at internal momenta above 800 MeV/c.

    nucl-thhep-phnucl-exPoS(2025)·0 citations
  2. 02

    Double shape quantum phase transitions in the SU3-IBM: new -soft phase and the shape phase transition from the new -soft phase to the prolate shape

    De-hao Zhao · Xiao-shen Kang · Li Gong · Ze-yu Yin · Tao Wang

    Shape quantum phase transition is an important topic in nuclear structure. In this paper, we begin to study the shape quantum phase transition in the SU3-IBM. In this new proposed model, spherical-like spectra was found to resolve the spherical nucleus puzzle, which is a new -soft rotational mode. In this paper, the shape phase transition along the new -soft line is first discussed, and then the neighbouring case at the prolate side is also studied. We find that double shape phase transitions occur along a single parameter path. The new -softness is really a shape phase and the shape phase transition from the new -soft phase to the prolate shape is found. The experimental support is also found and Pd may be the critical nucleus.

    nucl-thnucl-exNucl.Sci.Tech.(2026)·6 citations
  3. 03

    Machine Learning for Extrapolating No-Core Shell Model Results to Infinite Basis

    R. E. Sharypov (1) · A. I. Mazur (1) · A. M. Shirokov (2) ((1) Pacific National University, Russia, (2) Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia)

    We utilize the machine learning to extrapolate to the infinite model space the no-core shell model (NCSM) results for the energies and rms radii of the 6He ground state and 6Li lowest states. The extrapolated energies and rms radii converge as the NCSM results from larger model spaces are included in the training dataset for ensemble of artificial neural networks thus enabling an accurate predictions for these observables.

    nucl-thJ.Subatomic Part.Cosmol.(2025)·2 citations
  4. 04

    Kaon-meson coupling from SU(3) flavour symmetry and application to antikaon condensed dense matter in neutron star

    Athira S.🇮🇳 · Monika Sinha🇮🇳 · Vivek Baruah Thapa🇮🇳 · Vishal Parmar🇮🇳

    Observations of massive pulsars suggest that the central density of neutron stars can exceed several times the nuclear saturation density, creating a favourable environment for the appearance of exotic states, such as strange and non-strange baryons, meson condensates, and deconfined quark matter. The antikaon condensate is the most studied and plausible candidate among meson condensates. However, little is known about the exact interaction mechanisms between antikaons and mediator mesons. In this work, we investigate these interactions by, for the first time, employing SU(3) flavor symmetry to study antikaon condensation in dense matter. We determine hadron couplings in the mesonic sector using SU(3) flavour symmetry. Among the three key parameters we calculate , the mixing angle between the octet meson and the singlet meson ; the ratio of the octet to singlet couplings ; and leave the weight factor that balances the symmetric and antisymmetric couplings as a free parameter to explore its impact on the system. Using this approach, we derive the couplings for antikaon interactions with both singlet and octet mesons in the nonet vector meson family and examine the corresponding implications for dense matter featuring antikaon condensation. Our findings reveal that the equation of state for dense matter becomes progressively stiffer with increasing values of , which delays the onset of antikaon condensation and increases the maximum achievable mass of neutron stars.

    nucl-thhep-phJCAP(2025)·2 citations
  5. 05

    Machine Learning Approach to Study of Low Energy Alpha-Deuteron Elastic Scattering using Phase Function Method

    Arushi Sharma · Ayushi Awasthi · Jyoti Sharma · Ishwar Kant · M. R. Ganesh Kumar · O.S. K. S. Sastri

    Central idea: To obtain the interaction potential using the inverse scattering method, we have employed the Physics-Informed Machine Learning (PIML) approach. In this framework, the machine learning algorithm is guided by the underlying physical laws, enabling the accurate extraction of the inverse scattering potential from the elastic scattering data. Methodology: As a reference potential, a combination of three smoothly joined Morse functions has been utilized, characterized by ten model parameters. These parameters are optimized in an iterative fashion using a Genetic Algorithm to ensure the best fit to the phase shifts extracted from the experimental scattering data. The process of optimization is guided by the computed scattering phase shifts by solving the phase equation using 5th order RK-method for the reference potential in each iteration Results: Our approach yields inverse potentials for both single and multi channel scattering. Using the Scattering Phase Shifts obtained from these inverse potentials, we calculate the partial cross-section to determine the resonance energies and decay width. The obtain values of resonance energies and decay width for 3D1, 3D2 and 3D3 states of alpha-deuteron are in correspondence with the experimental results. Conclusion: It can be concluded that our machine learning-based approach for constructing the inverse potential offers a novel and complementary technique to existing direct methods.

    nucl-th2 citations
  6. 06

    Holographic hybrid stars with slow phase transitions

    M. Aleixo🇧🇷 · C. H. Lenzi🇧🇷 · M. Dutra🇧🇷 · O. Lourenço🇧🇷 · W. de Paula🇧🇷

    The - holographic model is used to describe the core of the hybrid star, composed by quark matter, while its crust is modeled from a hadronic relativistic mean field (RMF) model capable of reproducing low-energy nuclear physics data as well as some astrophysical observations. The - brane configuration and the RMF model lead to an equation of state that is used to solve the Tolman-Oppenheimer-Volkoff equations. For different model parameters, the mass-radius diagram is presented. The conditions for the dynamic stability of stellar configurations are discussed, considering the radial oscillation criterion for hybrid stars with slow phase transitions. Strikingly, it is shown that the models generate stable star configurations with a core of quarks. We compare our results with NICER observational data for the pulsars PSR J0030+0451 and PSR J0740+6620 and show that the compact stars generated from this method fall within the corresponding observational regions.

    nucl-thhep-phPRD(2025)·1 citation
  7. 07

    High-order fluctuations of temperature in hot QCD matter

    Jinhui Chen🇨🇳 · Wei-jie Fu🇨🇳 · Shi Yin🇩🇪 · Chunjian Zhang🇨🇳

    A new thermodynamic state function is introduced to describe the thermodynamics relevant for the mean transverse momentum fluctuations of charged particles in heavy-ion collisions, which allows us to compute the temperature fluctuations of different orders in hot quantum chromodynamics (QCD) matter for the first time. Consequently, it is found that the temperature fluctuations are suppressed remarkably as the system transitions from the hadron resonance gas (HRG) to the quark-gluon plasma (QGP) with increasing temperature or baryon chemical potential, alongside a negative skewness. This is attributed to the general fact that the heat capacity of QCD matter increases significantly in QGP in comparison to that in HRG. These predictions provide a candidate observable to discover the thermodynamic temperature fluctuations in upcoming heavy-ion collision experiments, which also paves a novel way to study QCD thermodynamics and QCD phase diagram through measurements of the mean transverse momentum fluctuations of charged particles.

    ↳ hep-phnucl-exnucl-thPRD(2026)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE