Nuclear Theory·nucl-th

Monday·April 7, 2025

11 papers—5 primary·6 cross-listed

01
[Submitted on 3 Apr 2025]
Is the central compact object in HESS J1731-347 a hybrid star with a quark core? An analysis with the constant speed of sound parametrization
Suman Pal🇮🇳 · Soumen Podder🇮🇳 · Gargi Chaudhuri🇮🇳
In this work, we investigate the possibility of the compact object in HESS J1731-347 with $M = 0.7 7_{- 0.17}^{+ 0.20} M_{⊙}$ and $R = 10. 4_{- 0.78}^{+ 0.86} k m$ to be a hybrid star with quark matter in the inner core. The observation of this low mass compact star dictates the use of softer equation of state which on the contrary cannot explain the massive compact stars. This poses a new challenge for the astrophysicists in their search for the equation of state of compact objects. The hybrid equations of state are constructed using the IUFSU parametrization based on the relativistic mean field (RMF) theory for the hadronic part and the generic constant speed of sound parametrization (CSS) for the phase transition to quark matter.The CSS framework is characterized by three key parameters, namely the transition density $(ρ_{t r})$ , the energy jumps $(Δ ε)$ and the speed of sound $(C_{s})$ . Here, our primary aim is to investigate the influence of individual CSS parameters on the formation of a object of small mass and radius compatible with HESS J1731-347 parameters. We have also examined the effect of hadronic parameters such as effective mass, symmetry energy, and the slope of the symmetry energy at saturation densities on the formation of this compact object.Finally our analysis suggests that, within a 1 $σ$ credible level, HESS J1731-347 aligns with the scenario of a stable hybrid star with early deconfinement and higher energy gap
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2504.02945 [pdf]
ApJ(2025)·14 citations
02
[Submitted on 3 Apr 2025]
A unified algorithm for multi-particle correlations between azimuthal angle and transverse momentum in ultra-relativistic nuclear collisions
Emil Gorm Dahlbæk Nielsen🇩🇰 · Nina Nathanson🇩🇰 · Kristjan Gulbrandsen🇩🇰 · You Zhou🇩🇰
Multi-particle correlations between azimuthal angle and mean transverse momentum are a powerful tool for probing size and shape correlations in the initial conditions of heavy-ion collisions. These correlations have also been employed to investigate nuclear structure, including potential nuclear shape phase transitions at the energy frontier. However, their implementation is highly nontrivial, and prior studies have been mostly limited to lower-order correlations, such as the modified Pearson correlation coefficient, $ρ (v_{n}^{2}, [p_{T}])$ . This paper presents a unified framework that employs a recursive algorithm, enabling the efficient evaluation of arbitrary-order correlations while maintaining computational efficiency. This framework is demonstrated using widely adopted transport models, including AMPT and HIJING. The proposed unified algorithm for multi-particle correlations between azimuthal angle and transverse momentum provides a systematic and efficient approach for multi-particle correlation analyses. Its application in experiments at the Relativistic Heavy Ion Collider and the Large Hadron Collider facilitates the exploration of nuclear structure at ultra-relativistic energies.
Comments:
10 pages, 3 figures, 1 table
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2504.03044 [pdf]
EPJC(2025)·4 citations
03
[Submitted on 4 Apr 2025]
Numerical Assessment of Convergence in the Post Form Ichimura-Austern-Vincent model
Jin Lei
The Ichimura-Austern-Vincent (IAV) model provides a powerful theoretical framework for describing inclusive breakup reactions. However, its post-form representation presents significant numerical challenges due to the absence of a natural cutoff in the transition matrix integration. This work presents a systematic assessment of convergence methods for post-form IAV calculations, comparing the bin method and the Vincent-Fortune approach. We demonstrate that while the bin method offers implementation simplicity, it exhibits strong parameter dependence that compromises numerical stability. In contrast, the Vincent-Fortune method, which employs complex contour integration, achieves reliable convergence without arbitrary parameters. We further introduce a novel hybrid approach that integrates finite-range distorted wave Born approximation (DWBA) with the Vincent-Fortune technique, combining the accuracy of finite-range treatment at short distances with the numerical stability of zero-range approximations in the asymptotic region. Numerical results for deuteron and $^{6}$ Li-induced reactions confirm the efficacy of this hybrid method, showing consistent agreement with experimental data while eliminating the convergence issues that plague traditional approaches. This advancement enables more reliable calculations of nonelastic breakup cross sections and facilitates the extension of the IAV formalism beyond DWBA to incorporate continuum-discretized coupled-channels (CDCC) wave functions for a more comprehensive treatment of breakup processes.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2504.03112 [pdf]
PRC(2025)·3 citations
04
[Submitted on 4 Apr 2025]
NucleiML: A machine learning framework of ground-state properties of finite nuclei for accelerated Bayesian exploration
Anagh Venneti · Chiranjib Mondal · Sk Md Adil Imam · Sarmistha Banik · Bijay K. Agrawal
The global behavior of the nuclear equation of state (EoS) is commonly studied using data from finite nuclei (FN), heavy-ion collisions, and astrophysical observations of neutron stars (NS). The constraints derived from FN such as binding energies and charge radii play the most crucial role in shaping the EoS up to saturation density. The computational cost associated with explicitly incorporating these constraints presents a significant challenge especially when the aim is to explore the model uncertainties rather than optimizing a single model. We address this by introducing NucleiML (NML), a machine learning framework trained on ground-state properties of a few finite nuclei generated by a relativistic mean-field model. NML allows us to integrate FN and NS properties within a Bayesian inference framework in an efficient manner. The results demonstrate reasonable accuracy and a speedup of $\sim 1 0^{4}$ times for calculation of FN properties for a single parameter set, yielding roughly $\sim 1 0^{3} \times$ speed up in the Bayesian framework. The present study makes the case for extending the work to a larger set of nuclei, potentially enabling future studies of NS properties to incorporate the whole nuclear chart.
Comments:
21 Pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2504.03333 [pdf]
1 citation
05
[Submitted on 4 Apr 2025]
Predictions in the superheavy region from the quark-meson coupling model QMC $π$ -III
Kay Marie M. Paglinawan (1) · Anthony W. Thomas (2) · Pierre A. M. Guichon (2) · Jirina R. Stone (3) ((1) Silliman University, Dumaguete City, Philippines, (2) CSSM and ARC Centre of Excellence for Dark Matter Particle Physics, University of Adelaide, SA, Australia, (3) Department of Physics (Astrophysics), University of Oxford, Oxford, UK)
The Quark-Meson Coupling (QMC) model establishes a self-consistent relationship between the quark structure dynamics of a nucleon and the relativistic mean fields that arise within the nuclear medium. The model has been successful in calculating the ground-state observables of finite nuclei and in predicting the properties of dense nuclear matter, as well as cold, nonaccreting neutron stars. This paper focuses on the latest predictions from the model for the superheavy region, encompassing energies and deformations. Despite utilizing significantly fewer model parameters, the results have consistently improved as the model evolved, yielding better predictions for binding energies.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2504.03498 [pdf]
PoS(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Is the central compact object in HESS J1731-347 a hybrid star with a quark core? An analysis with the constant speed of sound parametrization

A unified algorithm for multi-particle correlations between azimuthal angle and transverse momentum in ultra-relativistic nuclear collisions

Numerical Assessment of Convergence in the Post Form Ichimura-Austern-Vincent model

NucleiML: A machine learning framework of ground-state properties of finite nuclei for accelerated Bayesian exploration

Predictions in the superheavy region from the quark-meson coupling model QMCπ-III

Affiliations

Predictions in the superheavy region from the quark-meson coupling model QMC $π$ -III