Nuclear Theory·nucl-th

Tuesday·August 19, 2025

19 papers—11 primary·8 cross-listed

12
[Submitted on 13 Aug 2025] (cross-list from hep-lat)
Thermodynamics of fermionic excitations in heavy-quark QCD
Kei Tohme🇯🇵 · Takahiro M. Doi🇯🇵 · Masakiyo Kitazawa🇯🇵 · Krzysztof Redlich🇵🇱 · Chihiro Sasaki🇵🇱
We investigate the thermodynamic properties of fermionic excitations in heavy-quark QCD on the lattice with Wilson fermions. The grand potential is calculated analytically in the hopping parameter expansion (HPE) on the basis of the cumulant expansion. Using the grand potential, we compute the quark number susceptibilities and their ratios up to next-to-leading order in the HPE. The ratio of fourth- to second-order susceptibilities is shown to be unity (nine) in the deconfined (confined) phase at the leading order. Excitation properties of baryonic and quark modes in each phase are also investigated utilizing the Boltzmann statistics. We obtain an analytic formula for the quark excitation energy in the deconfined phase, while that for baryonic excitations in the confined phase is decomposed into flavor multiplets.
Comments:
9 pages
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2508.09927 [pdf]
PRD(2025)·4 citations
13
[Submitted on 15 Aug 2025] (cross-list from hep-ph)
Thermalization of Bottomonium in the Quark-Gluon Plasma
Nora Brambilla🇩🇪 · Tom Magorsch🇩🇪 · Antonio Vairo🇩🇪
We study the approach to equilibrium of bottomonium in the quark-gluon plasma within the open quantum system framework. We perform large-scale simulations of the long-time behavior in three dimensions using the quantum trajectory method to observe the emergence of steady states and determine the timescale of thermalization in position-, angular-momentum-, and color-space. We find that the thermalization timescale increases with decreasing temperature and decreasing coupling to the medium, which is given by transport coefficients of the medium. Additionally, we observe that the steady states exhibit small corrections to the Gibbs state due to medium interactions and show that these corrections diminish for weaker medium coupling and higher temperature. At a temperature of $450$ MeV, quarkonium relaxes to a state that is approximately thermal, with the most significant correction being a smaller overlap of the $1 S$ state with respect to the Gibbs state. We compare these findings with the master equation obtained at leading order in the expansion of the binding energy over the temperature, which we find to have a trivial steady state.
Comments:
34 pages, 18 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2508.11743 [pdf]
JHEP(2026)·6 citations
14
[Submitted on 16 Aug 2025] (cross-list from astro-ph.HE)
Limitations in constraining neutron star radii and nuclear properties from inspiral gravitational wave detections
Zhenyu Zhu🇺🇸 · Richard O'Shaughnessy🇺🇸
We investigate the constraints on the neutron star equation of state (EoS) and nuclear properties achievable with third-generation gravitational wave detectors using the Fisher information matrix approach within the relativistic mean field (RMF) theory. Assuming an optimistic binary neutron star (BNS) merger rate, we generate simulated inspiral gravitational wave (GW) signals corresponding to one year of observation. From these simulated data, we compute the covariance matrix and posterior distributions for nuclear properties and EoS. Our results show that the EoS can be tightly constrained, particularly in the density range between one and four times nuclear saturation density. However, due to the scarcity of low-mass neutron stars in the GW sample, the EoS at sub-saturation densities remains poorly constrained. Thus, in turn, leads to weaker constraints on neutron star radii, as the radii are sensitive to the low-density EoS. Additionally, we present the expected correlations among nuclear parameters in general and plots of the inferred symmetry energy in particular, which represent degeneracies in their influence on the EoS and make them difficult to be constrained through GW observations alone. These highlights inherent limitations of inspiral GW signals in probing dense matter properties. Therefore, precise radius measurements, post-merger GW observations, and supplementary constraints from terrestrial nuclear experiments remain essential for a comprehensive understanding of dense matter.
Comments:
10 pages, 4 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2508.11875 [pdf]
PRD(2026)·4 citations
15
[Submitted on 16 Aug 2025] (cross-list from hep-ph)
In-medium heavy quark-antiquark $T$ -matrix without partial wave expansion
Anurag Tiwari🇨🇳 · Min He🇨🇳
The T-matrix of the heavy quark-antiquark ( $Q Q ˉ$ ) pair interacting through a screened Cornell potential in the quark-gluon plasma (QGP) is computed without employing the partial wave expansion. This is compared with the results obtained using the conventional method of partial wave expansion. Through a comprehensive survey over a range of screening mass and center-of-mass energy, which, when combined, determine the orbital angular momentum involved in the scattering through the associated force range and incident momentum, it is demonstrated that a substantial number of partial wave terms are necessary to precisely match the full scattering amplitude directly obtained from the method without partial wave expansion. For moderate screening masses (corresponding to one to two times the crossover transition temperature) and center-of-mass energy, the number of partial waves required for satisfactory matching turns out as large as 10-20, substantially larger than what one would expect based on simply measuring the magnitudes of the first few partial wave amplitudes. This highlights the efficiency of the new method in directly obtaining the full scattering amplitude needed for further computation of phenomenological observables. We also employ the new method to calculate the T-matrix at center-of-mass energies below the $Q Q ˉ$ mass threshold, and demonstrate the presence of bound states of different orbital quantum numbers simultaneously in a single energy scan.
Comments:
14 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2508.11895 [pdf]
PRC(2026)·1 citation
16
[Submitted on 16 Aug 2025] (cross-list from hep-ph)
Simulation of heavy quarkonium equilibration in the quark-gluon plasma
Shouxing Zhao🇨🇳 · Min He🇨🇳
We simulate the heavy quarkonium equilibration through transport in a static and homogeneous quark-gluon plasma (QGP) box within the semi-classical Boltzmann approach incorporating both the leading-order and next-to-leading-order dissociation and regeneration reactions. The scattering amplitudes involved are taken from perturbative computations based on effective color-electric dipole coupling of the heavy quarkonium with thermal gluons. By coupling the Langevin simulation of single heavy quark diffusion and the Boltzmann transport of the heavy quarkonium in a real-time fashion, we demonstrate how the kinetic and chemical equilibrium of heavy quarkonium with single heavy quarks in the medium is achieved in terms of both the bound state's yields and momentum distributions. The pertinent equilibration time turns out to be comparable to the lifetime of the QGP created in the most central heavy-ion collisions at the LHC energies. The role of the intricate interplay between the open and hidden heavy sector in the process of equilibration is highlighted. This work provides a dynamical way of understanding the phenomenological success of statistical hadronization model for charmonium production in relativistic heavy-ion collisions, and also paves the way for realistic phenomenological applications to heavy quarkonium transport.
Comments:
14 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2508.11897 [pdf]
PRD(2025)·1 citation
17
[Submitted on 18 Aug 2025] (cross-list from hep-ph)
Scaling behaviour of charged particles generated in Xe $-$ Xe collisions at $s_{NN}$ = 5.44 TeV using the AMPT model
Zarina Banoo🇮🇳 · Ramni Gupta🇮🇳 · Salman K. Malik🇮🇳 · Sheetal Sharma🇮🇳 · Fakhar Ul Haider🇮🇳 · Balwan Singh🇮🇳
The spatial configurations of particles produced in the kinematic phase space during a heavy-ion collision reflect the characteristics of the system created in the collision. The scaling behaviour of the multiplicity fluctuations is studied for the charged particles generated in Xe--Xe collisions at $s_{NN}$ ~=~5.44~TeV using the String Melting (SM) mode of the AMPT (A Multi-Phase Transport) model. The scaling behaviour of the normalized factorial moments ( $F_{q}$ ) gives significant information about the dynamics of the system under study. A linear power-law growth of the $F_{q}$ with the increasing phase space resolution, termed as intermittency, is investigated. The anomalous fractal dimension $D_{q}$ is determined, which is linked to the self-similarity and fractal nature of the particle emission spectra, whose dependence on the order of the moment ( $q$ ) is characterised by the intermittency index ( $φ_{q}$ ). Relating $q^{th}$ order Normalised Factorial Moment (NFM) with $F_{2}$ , the scaling exponent ( $ν$ ) is determined that quantifies the dynamics of the system created by these collisions and is analyzed for its dependence on the transverse momentum bin width ( $Δ p_{T}$ ). Results presented may be interpreted as model predictions and baseline expectations.
Comments:
10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2508.12796 [pdf]
NPA(2026)·0 citations
18
[Submitted on 18 Aug 2025] (cross-list from hep-lat)
Toward extracting scattering phase shift from integrated correlation functions V: complex $ϕ^{4}$ field model in $3 + 1$ dimensions
Peng Guo🇺🇸 · Frank X. Lee🇺🇸 · Andrei Alexandru🇺🇸
In Ref.~\cite{Guo:2024zal} and associated studies, a relativistic finite-volume formalism in $1 + 1$ dimensions is proposed to extract infinite-volume scattering phaseshift. It is based on the difference of integrated correlation functions (ICF) rather than energy spectrum in the finite volume, and can be regarded as complementary to the well-known Lüscher} formalism. In the present work, the formalism is further extended into $3 + 1$ dimensional spacetime. The aim is to explore and demonstrate the challenges in applying the formalism to more practical settings. Specifically, Monte Carlo simulations of a complex $ϕ^{4}$ relativistic field model are carried out in both 2+1 and 3+1 dimensions on lattices of varying sizes, and phaseshifts for the contact interaction are extracted from the formalism using modest computing resources.
Comments:
Compared to the published version in PRD, this update has improved figures for 3+1 dimensions from higher statistics
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2508.12881 [pdf]
PRD(2025)·4 citations
19
[Submitted on 18 Aug 2025] (cross-list from hep-ph)
Polarized electromagnetic radiation by chiral media with time-dependent chiral chemical potential
Kirill Tuchin🇺🇸
We investigate photon production from media characterized by a time-dependent chiral chemical potential $μ_{5} (t)$ . We first consider the chiral anomaly as a small perturbation and show that $μ_{5} \to 2 γ$ process generates non-polarized radiation, as the probabilities of producing right and left-handed photons are equal. In chiral semimetal with a vanishing chiral chemical potential but a finite separation of Weyl nodes, $Δ (t)$ , the photon production vanishes at the leading order of perturbation theory. We then employ the method of Bogolyubov transformation to obtain the photon spectrum that sums up all powers of $μ_{5}$ . Employing the exactly solvable model $μ_{5} (t) \propto A + B tanh (t / τ)$ , we demonstrate that the spectrum exhibits strong circular polarization, whose direction is determined by the sign of $μ_{5}$ . The spectrum contains resonances associated with the instability of the electromagnetic field in chiral media. We discuss potential phenomenological applications of these findings.
Comments:
9 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); cond-mat.mtrl-sci (cond-mat.mtrl-sci); Nuclear Theory (nucl-th)
arXiv:
2508.12923 [pdf]
PLB(2026)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE