Nuclear Theory·nucl-th

Tuesday·February 18, 2025

10 papers—3 primary·7 cross-listed

01
[Submitted on 15 Feb 2025]
Conformality Thresholds in Neutron Stars
Michał Marczenko
The dense-matter equation of state (EOS) under neutron-star conditions is investigated. We focus on the qualitative behavior of the speed of sound and its average. We characterize and compare the theoretical criteria for identifying nearly conformal matter. We find that the consistency of these criteria in determining the onset of conformal matter is dictated by the combined state-of-the-art theoretical and astrophysical constraints.
Comments:
contribution to EMMI Workshop at the University of Wrocław - Aspects of Criticality II
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2502.10847 [pdf]
J.Subatomic Part.Cosmol.(2025)·4 citations
02
[Submitted on 16 Feb 2025]
Stochastic baryon charge transport in relativistic hydrodynamics
Nicolas Borghini🇩🇪 · Baochi Fu🇩🇪 · Sören Schlichting🇩🇪
We utilize 3+1D stochastic hydrodynamics to study correlations and fluctuations of baryon charge in high-energy heavy-ion collisions. The baryon charge fluctuations are important observables to probe the QCD phase diagram, yet a dynamical description with stochastic hydrodynamics remains challenging due to numerical instabilities and high computational demands. In this work, we employ a linearized approach, allowing us to separately simulate the background energy-momentum evolution of a charge-neutral fluid and the stochastic baryon transport processes, thereby largely reducing computational cost while maintaining sufficient accuracy. We implement this linearized stochastic charge evolution in the viscous hydrodynamic code MUSIC, and find that it nicely describes the two-point correlation of 1+1D analytical solutions for various equations of state and transport coefficients. In particular, the hydrodynamic calculations demonstrate how different rapidity separations probe charge fluctuations originating at different times of the evolution. We also investigate the net baryon correlations after the Cooper--Frye freeze out, which show good consistency with the analytical calculations and indicate that these fluctuation-induced correlations are sensitive to the baryon diffusion coefficient.
Comments:
16 pages, 17 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2502.11202 [pdf]
PRD(2025)·0 citations
03
[Submitted on 16 Feb 2025]
Quantum Dynamical Microscopic Approach to Stellar Carbon Burning
Grant Close · Paul Stevenson · Alexis Diaz-Torres
The process of carbon burning is vital to understanding late stage stellar evolution of massive stars and the conditions of certain supernovae. Carbon burning is a complex problem, involving quantum tunnelling and nuclear molecular states. Quantum dynamical calculations of carbon burning are presented, combining the time-dependent wave-packet method and the density-constrained time-dependent Hartree-Fock (DC-TDHF) approach. By limiting the contribution of triaxial molecular configurations to fusion, we demonstrate that the DC-TDHF interaction potential successfully explains the appearance of some resonant structures in the sub-barrier fusion cross-section. This result shows the critical role of nucleon-nucleon interactions in the 12C + 12C fusion resonances observed at astrophysical energies.
Comments:
9 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2502.11240 [pdf]
PLB(2025)·5 citations
04
[Submitted on 5 Feb 2025] (cross-list from physics.plasm-ph)
Nuclear Fusion Enhancement by Heavy Nuclear Catalysts
Christopher Grayson🇭🇺 · Johann Rafelski🇺🇸
We seek to understand the effect of high electron density in the proximity of a heavy nucleus on the fusion reaction rates in a hot plasma phase. We investigate quantitatively the catalytic effect of gold ( $Z = 79$ ) ions embedded in an electron plasma created due to plasmonic focusing of high-intensity short laser pulses. Using self-consistent strong plasma screening, we find highly significant changes in the internuclear potential of light elements present nearby. For gold, we see a $14$ keV change in the internuclear potential near the nuclear surface, independent of the long-distance thermal Debye-Hückel screening. The dense polarization cloud of electrons around the gold catalyst leads to a $\sim 1.5$ enhancement of proton-boron ( $^{11}$ B) fusion above $T = 100$ keV.
Subjects:
Plasma Physics (physics.plasm-ph); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2502.07804 [pdf]
Eur.Phys.J.ST(2025)·2 citations
05
[Submitted on 14 Feb 2025] (cross-list from hep-lat)
Lattice QCD constraints on the critical point from an improved precision equation of state
Szabolcs Borsanyi🇩🇪 · Zoltan Fodor🇩🇪 · Jana N. Guenther🇩🇪 · Paolo Parotto🇮🇹 · Attila Pasztor🇭🇺 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸 · Chik Him Wong🇩🇪
In this Letter we employ lattice simulations to search for the critical point of quantum chromodynamics (QCD). We search for the onset of a first order QCD transition on the phase diagram by following contours of constant entropy density from imaginary to real chemical potentials under conditions of strangeness neutrality. We scan the phase diagram and investigate whether these contours meet to determine the probability that the critical point is located in a certain region on the $T - μ_{B}$ plane. To achieve this we introduce a new, continuum extrapolated equation of state at zero density with improved precision using lattices with $N_{τ} = 8, 10, 12, 16$ timeslices, and supplement it with new data at imaginary chemical potential. The current precision allows us to exclude, at the $2 σ$ level, the existence of a critical point at $μ_{B} < 450$ ~MeV.
Comments:
7 + 5 Pages with a Supplemental Material in the same file
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2502.10267 [pdf]
PRD(2025)·60 citations
06
[Submitted on 14 Feb 2025] (cross-list from hep-ph)
Complex potential and open system applications in heavy-ions and cold atoms
Yukinao Akamatsu🇯🇵
Since the discovery of the complex potential of quarkonium at high temperatures, quarkonium has been regarded as an open quantum system in the quark-gluon plasma. Recently, a similar issue regarding in-medium bound states of impurities has also emerged in particle physics and cold atomic physics. We will provide an overview of recent advancements in understanding key quantities such as complex potential and transport coefficients for heavy impurities in finite temperature QCD and cold atomic systems.
Comments:
13 pages, 6 figures, Proceedings of the XVIth Quark Confinement and the Hadron Spectrum Conference (QCHSC24)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2502.10518 [pdf]
PoS(2025)·0 citations
07
[Submitted on 16 Feb 2025] (cross-list from hep-ph)
Heavy-flavor multimodal fragmentation to $S$ -wave pentacharms at next-generation hadron colliders
Francesco Giovanni Celiberto🇪🇸
We investigate the leading-power fragmentation of fully charmed pentaquark states ( $S$ -wave $∣ c c ˉ ccc ⟩$ pentacharms) at hadron colliders. We introduce a new set of multimodal collinear fragmentation functions, named PQ5Q1.0. They rely on an enhanced calculation of the initial-scale input for the constituent heavy-quark fragmentation channel, making them well suited to describe the short-distance emission of either a compact multicharm state or a dicharm-charm-dicharm configuration. To explore phenomenological implications, we use the (sym)JETHAD multimodular interface to study NLL/NLO $^{+}$ semi-inclusive production rates for pentacharm-plus-jet systems at the forthcoming HL-LHC and the future FCC. Our analysis represents a further step toward bridging the domains of hadronic structure, precision QCD, and exotic matter.
Comments:
49 pages, 9 figures, 245 references, published in Eur. Phys. J. C. One novel set of multimodal (direct multicharm and diquark-like initial-scale inputs) "PentaQuarks with 5 heavy Quarks" (PQ5Q1.0) NLO collinear fragmentation functions released in LHAPDF format and publicly available from https://github.com/FGCeliberto/Collinear_FFs/
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2502.11136 [pdf]
EPJC(2025)·15 citations
08
[Submitted on 17 Feb 2025] (cross-list from hep-ph)
Flavor dependence of Energy-energy correlators
Liliana Apolinário🇵🇹 · Raghav Kunnawalkam Elayavalli🇺🇸 · Nuno Olavo Madureira🇵🇹 · Jun-Xing Sheng🇺🇸 · Xin-Nian Wang🇨🇳 · Zhong Yang🇺🇸
Energy-energy correlators (EECs) within high energy jets serve as a key experimentally accessible quantity to probe the scale and structure of the quark-gluon plasma (QGP) in relativistic heavy-ion collisions. The CMS Collaboration's first measurement of the modification to the EEC within single inclusive jets in Pb+Pb collisions relative to p+p collisions reveals a significant enhancement at small angles, which may arise from jet transverse momentum $p_{T}$ selection biases due to jet energy loss. We investigate the dependence of jet EECs on the flavor of the initiating parton. The EEC distribution of a gluon jet is broader and the peak of transition from perturbative to non-perturbative regime occurs at a larger angle than a quark jet. Such flavor dependence leads to the different EECs for $γ$ -jets and single inclusive jets due to their different flavor composition. It is also responsible for a colliding energy dependence of EECs of single inclusive jets at fixed jet energy. We also investigate the impact of flavor composition variation on the $p_{T}$ dependence of the jet EEC. We further propose that a change in the gluon jet fraction in A+A collisions compared to p+p can also contribute to a non-negligible enhancement of the medium modified EEC at small angles. Using the \textsc{Jewel} model, we predict the reduction of the gluon jet fraction in A+A collisions and estimate its impact on the EEC.
Comments:
This version includes revised figures and additional references
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2502.11406 [pdf]
PRD(2025)·29 citations
09
[Submitted on 17 Feb 2025] (cross-list from astro-ph.HE)
Constraining first-order phase transition inside neutron stars with application of Bayesian techniques on PSR J0437-4715 NICER data
Chun Huang · Shashwat Sourav
Understanding the existence of exotic matter phases and phase transitions within the core of neutron stars is crucial to advancing our knowledge of cold-dense matter physics. Recent multi-messenger observations, including gravitational waves from neutron star mergers and precise X-ray data from NASA's Neutron Star Interior Composition Explorer (NICER) mission, have significantly constrained the neutron star equation of state (EOS). This study investigates the effects of phase transitions in neutron stars, focusing on NICER's latest observation of PSR J0437--4715. We employ Bayesian inference techniques to evaluate the presence of first-order phase transitions using a piecewise polytropic EOS model. Our analysis incorporates data from multiple NICER sources, to refine constraints on key phase transition parameters, including critical density and transition depth. We find that including data from PSR J0437--4715 improves the evidence of phase transitions and tightens the EOS constraints, especially at higher densities. However, Bayes factor analysis only indicates a slight preference for models without phase transitions and current observational precision is insufficient to draw definitive conclusions. In particular, this polytropic model identifies the critical phase transition mass of neutron stars as being close to 1.4 solar masses, which coincides with the approximate mass range of PSR J0437--4715. This work emphasizes the importance of precise measurements of PSR J0437--4715 for deepening our understanding of neutron star interiors and exploring potential new physics at extreme densities.
Comments:
Published version on ApJ
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2502.11976 [pdf]
ApJ(2025)·24 citations
10
[Submitted on 17 Feb 2025] (cross-list from hep-lat)
Lattice QCD Study of Pion Electroproduction and Weak Production from a Nucleon
Yu-Sheng Gao🇨🇳 · Zhao-Long Zhang🇨🇳 · Xu Feng🇨🇳 · Lu-Chang Jin🇺🇸 · Chuan Liu🇨🇳 · Ulf-G.Meißner🇩🇪
Quantum fluctuations in QCD influence nucleon structure and interactions, with pion production serving as a key probe of chiral dynamics. In this study, we present a lattice QCD calculation of multipole amplitudes at threshold, related to both pion electroproduction and weak production from a nucleon, using two gauge ensembles near the physical pion mass. We develop a technique for spin projection and construct multiple operators for analyzing the generalized eigenvalue problem in both the nucleon-pion system in the center-of-mass frame and the nucleon system with nonzero momentum. The numerical lattice results are then compared with those extracted from experimental data and predicted by low-energy theorems incorporating one-loop corrections.
Comments:
13 pages, 6 figures, version accepted by PRL
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2502.12074 [pdf]
PRL(2025)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE