Nuclear Theory·nucl-th

Tuesday·June 3, 2025

16 papers—5 primary·11 cross-listed

01
Role of thermal fluctuations in nucleation of three-flavor quark matter
Mirco Guerrini🇮🇹 · Giuseppe Pagliara🇮🇹 · Andrea Lavagno🇮🇹 · Alessandro Drago🇮🇹
We present a framework that aims to investigate the role of thermal fluctuations of the matter composition and color-superconductivity in the nucleation of three-flavor deconfined quark matter in the typical conditions of high-energy astrophysical systems related to compact stars. It is usually assumed that the flavor composition is locally fixed during the formation of the first seed of deconfined quark matter since weak interaction acts too slowly to re-equilibrate flavors. However, the matter composition fluctuates around its average equilibrium values at the typical temperatures of high-energy astrophysical processes. Here, we extend our previous two-flavor nucleation formalism to a three-flavor case. We develop a thermodynamic framework incorporating finite-size effects and thermal fluctuations of local composition to compute the nucleation probability as the product of droplet formation and composition fluctuation rates. Moreover, we discuss the role of color-superconductivity in nucleation, arguing that it can play a role only in systems larger than the typical coherence length of diquark pairs. We found that thermal fluctuations of the matter composition lead to lowering the potential barrier between the metastable hadronic phase and the stable quark phase. Moreover, the formation of diquark pairs reduces the critical radius and thus the potential barrier in the low baryon density and temperature regime.
nucl-thastro-ph.HEUniverse(2025)·3 citations
02
Learning about neutron star composition from the slope of the mass-radius diagram
Márcio Ferreira🇵🇹 · Constança Providência🇵🇹
The slope of the neutron star mass-radius curve, $d M / d R$ , is studied to understand the information it may carry about the composition of neutron stars, particularly with regard to the presence of non-nucleonic degrees of freedom. This study uses two large sets of relativistic mean-field equations of state with either nucleonic or nucleonic and hyperonic degrees of freedom, and imposes constraints obtained from GW170817 and the pulsars PSR J0030+0451 and PSR J0740+6620. It is shown that: i) some mass-radius curves are characterized by a negative slope from one solar mass up to the maximum mass; ii) other equations of state (EoS) have a positive slope for a given range of masses below the maximum star mass. Within the set of models considered, the first set includes only a very small number of hyperonic EoS: less than 0.5\% of the total number of hyperonic stars and approximately one third of the nucleonic EoS. We have also analyzed the sign of the slope for neutron star masses of 1.2, 1.4 and 1.8 $M_{⊙}$ . Only approximately 1\% of hyperonic equations of state (EoS) predict a negative slope for 1.4 $M_{⊙}$ stars, whereas over 90\% of nucleonic stars have a negative slope at this mass. Finally, almost all stars have a negative slope at 1.8 $M_{⊙}$ . A positive slope at 1.4 $M_{⊙}$ may indicate the presence of non-nucleonic degrees of freedom within neutron stars. The nuclear matter property that distinguishes the different scenarios most clearly is the curvature of the symmetry energy. Nucleonic EoSs with a positive slope $d M / d R$ predict the highest values, which can exceed 100 MeV.
nucl-thastro-ph.HEhep-phPRD(2025)·12 citations
03
Perspectives for hyperon and hypernuclei physics
Jin-Hui Chen🇨🇳 · Li-Sheng Geng🇨🇳 · Emiko Hiyama🇯🇵 · Zhi-Wei Liu🇨🇳 · Josef Pochodzalla🇩🇪
Hypernuclei, nuclei containing one or more hyperons, serve as unique laboratories for probing the non-perturbative quantum chromodynamics (QCD). Recent progress in hypernuclear physics, driven by advanced experimental techniques and theoretical innovations, is briefly reviewed with a focus on key findings and unresolved challenges, such as the precise determination of the hypertriton binding energy, investigations of charge symmetry breaking in mirror hypernuclei, and the search for exotic systems, including the neutral nn $Λ$ state. Experimental breakthroughs, including invariant-mass analyses and femtoscopy studies in heavy-ion collisions, as well as high-resolution $γ$ -spectroscopy, have enabled precise studies of light hypernuclei and offered critical insights into the hyperon-nucleon interaction. Theoretical progress, including ab initio calculations based on chiral effective field theory and lattice QCD, has further enhanced our understanding of hyperon-nucleon and hyperon-hyperon interactions.
nucl-thnucl-exChin.Phys.Lett.(2025)·18 citations
04
Transport Theory and Correlation Measurements: Coming to Terms on Emission Sources
Pierre Nzabahimana · Pawel Danielewicz · Giuseppe Verde
Two-particle correlations play a pivotal role in understanding the space-time characteristics of particle emission in Heavy-ion collisions. These characteristics are typically represented by a relative emission source and can be obtained using transport model simulations such as the Boltzmann- Uehling-Uhlenbeck (BUU) transport model. In this paper, we utilize the BUU transport model to simulate the p-p source. Subsequently, we integrate this source and the p-p kernel within the KP formula to calculate the correlations. By comparing the correlations obtained from the BUU simulation with those obtained using imaging methods, such as the deblurring method, we aim to gain a deeper understanding of the impact of fast and slow emissions on the measured correlations. Specifically, this comparison is used as a tool to determine a function (tail) that represents the relative distribution of the particle pair from secondary decay emissions. Thus, we correct the BUU source function by incorporating a tail to account for the contribution of secondary decay emissions, which cannot be accurately captured by BUU simulations. Resulting source function reproduces the features in the measured correlations. To illustrate our approach, we examine p-p correlations measured in Ar + Sc reactions at E/A = 80 MeV, considering both momentum-independent and momentum-dependent nuclear equations of state (EOS).
nucl-th4 citations
05
Contact potentials in presence of a regular finite-range interaction using dimensional regularization and the $N / D$ method
David R. Entem🇪🇸 · Juan Nieves🇪🇸 · Jose Antonio Oller🇪🇸
We solve the Lippman-Schwinger equation (LSE) with a kernel that includes a regular finite-range potential and additional contact terms with derivatives. We employ distorted wave theory and dimensional regularization, as proposed in Physics Letters B 568 (2003) 109. We analyze the spin singlet nucleon-nucleon $S -$ wave as case of study, with the regular one-pion exchange (OPE) potential in this partial wave and up to $O (Q^{6})$ (six derivatives) contact interactions. We discuss in detail the renormalization of the LSE, and show that the scattering amplitude solution of the LSE fulfills exact elastic unitarity and inherits the left-hand cut of the long-distance OPE amplitude. Furthermore, we proof that the LSE amplitude coincides with that obtained from the exact $N / D$ calculation, with the appropriate number and typology of subtractions to reproduce the effective range parameters taken as input to renormalize the LSE amplitude. The generalization to higher number of derivatives is straightforward.
nucl-thhep-phPRD(2025)·4 citations
06
A New State of Matter between the Hadronic Phase and the Quark-Gluon Plasma?
Yuki Fujimoto🇺🇸 · Kenji Fukushima🇯🇵 · Yoshimasa Hidaka🇯🇵 · Larry McLerran🇺🇸
Lattice-QCD simulations and theoretical arguments hint at the existence of an intermediate phase of strongly interacting matter between a confined hadron gas and a deconfined Quark-Gluon Plasma (QGP). We qualitatively and semi-quantitatively explore and differentiate the phase structures in the temperature window from the QCD pseudo-critical temperature $T_{c} ≃ 160 MeV$ to the pure-gluonic deconfinement temperature $T_{d} ≃ 285 MeV$ . We propose a three-regime picture using a hadron resonance gas (HRG) description augmented with the glueball spectrum based on the analysis of a large number, $N_{c}$ , of colors. We estimate the entropy density from our model to confirm that the lattice-QCD data are bracketed with three regimes, i.e., a hadron gas, a QGP, and a new phase for $T_{c} ≲ T ≲ T_{d}$ . In this new phase that we name a Spaghetti of Quarks with Glueballs (SQGB), thermal degrees of freedom of quarks are deconfined, yet gluons remain confined in glueballs. Since the Hagedorn temperature, $T_{H} \sim 285 MeV$ , is universal in the meson and the glueball sectors, in the infinite $N_{c}$ limit, the phase diagram in the plane of the baryon chemical potential and the temperature is reduced to the one with the confined and deconfined phases and Quarkyonic Matter at high density. At large but finite $N_{c}$ , an SQGB window may open between these phases. We point out that the SQGB has interesting similarities with Quarkyonic Matter and that this matter in the large $N_{c}$ limit is confined as measured by the interaction between heavy quarks, but behaves in other respects like a quasi-free gas of quarks. As a result of the extrapolation to $N_{c} = 3$ , we present a revised phase diagram with the SQGB phase bounded by thermal crossovers. Finally, we give a quantitative analysis of chiral symmetry restoration in the SQGB phase.
↳ hep-phhep-latnucl-thPRD(2025)·35 citations
07
Comparing effective temperatures in standard and Tsallis distributions from transverse momentum spectra in small collision systems
Peng-Cheng Zhang🇨🇳 · Pei-Pin Yang🇨🇳 · Ting-Ting Duan🇨🇳 · Hailong Zhu🇨🇳 · Fu-Hu Liu🇨🇳 · Khusniddin K. Olimov🇺🇿
The transverse momentum ( $p_{T}$ ) spectra of identified light charged hadrons, specifically bosons ( $π^{\pm}$ and $K^{\pm}$ ) as well as fermions [ $p (p ˉ)$ ], produced in small collision systems, namely deuteron-gold (d+Au) and proton-proton (p+p) collisions at the top energy of the Relativistic Heavy Ion Collider (RHIC) with a center-of-mass energy of $s_{N N} = 200$ GeV, are investigated in this paper. In present study, d+Au collisions are categorized into three centrality classes: central (0--20\%), semi-central (20--40\%), and peripheral (40--100\%) collisions. Various types of distributions, including standard [Bose-Einstein (Fermi-Dirac) and Boltzmann] and Tsallis distributions, are employed to fit the same $p_{T}$ spectra to derive different effective temperatures denoted as $T_{e f f}$ . The results indicate that $T_{e f f}$ values obtained from Bose-Einstein, Boltzmann, Fermi-Dirac, and Tsallis distributions exhibit systematically a decreasing trend. Meanwhile, these $T_{e f f}$ values also show a decreasing trend with a decrease in collision centrality. Furthermore, based on the spectra of given particles, a perfect linear relationship is observed between different pairwise combinations of $T_{e f f}$ derived from both Boltzmann and Bose-Einstein (Fermi-Dirac) distributions as well as between Tsallis and Bose-Einstein (Fermi-Dirac) distributions.
↳ hep-phhep-exnucl-exnucl-thIndian J.Phys.(2026)·2 citations
08
Initial condition for the Balitsky-Kovchegov equation at next-to-leading order
Carlisle Casuga🇫🇮 · Henri Hänninen🇫🇮 · Heikki Mäntysaari🇫🇮
We determine the initial condition of the Balitsky-Kovchegov evolution equation at next-to-leading order (NLO) accuracy using HERA deep inelastic scattering data. Posterior distributions characterizing the initial condition are extracted using Bayesian inference. The total cross section and charm quark production data from HERA are found to provide stringent constraints on the posterior. These distributions quantify the uncertainty in the initial condition and serve as necessary input for propagating uncertainties to all NLO calculations within the Color Glass Condensate framework.
↳ hep-phnucl-thPRD(2025)·16 citations
09
Regularization Prescription for the Mixing Between Nonlocal Gluon and Quark Operators
Yao Ji🇨🇳 · Zhuoyi Pang🇨🇳 · Fei Yao🇨🇳 · Jian-Hui Zhang🇨🇳
It is well-known that in the study of mixing between nonlocal gluon and quark bilinear operators there exists an ambiguity when relating coordinate space and momentum space results, which can be conveniently resolved through Mellin moments matching in both spaces. In this work, we show that this ambiguity is due to the lack of a proper regularization prescription of the singularity that arises when the separation between the gluon/quark fields approaches zero. We then demonstrate that dimensional regularization resolves this issue and yields consistent results in both coordinate and momentum space. This prescription is also compatible with lattice extractions of parton distributions from nonlocal operators.
↳ hep-phhep-latnucl-exnucl-thPRD(2026)·0 citations
10
Exponential speedup in quantum simulation of Kogut-Susskind Hamiltonian via orbifold lattice
Georg Bergner🇩🇪 · Masanori Hanada🇬🇧 · Emanuele Mendicelli🇬🇧
We demonstrate that the orbifold lattice Hamiltonian -- an approach known for its efficiency in simulating SU( $N$ ) Yang-Mills theory and QCD on digital quantum computers -- can reproduce the Kogut-Susskind Hamiltonian in a controlled limit. We show that it emerges naturally as the infinite scalar mass limit of the orbifold lattice formulation, even at finite lattice spacing. Our analysis provides both a general analytical framework applicable to SU( $N$ ) gauge theories in arbitrary dimensions and specific numerical evidence for $(2 + 1)$ -dimensional SU( $N$ ) Yang-Mills theories ( $N = 2, 3$ ). Using Euclidean path integral methods, we quantify the approach to this limit by comparing the standard Wilson action with the orbifold lattice action, matching lattice parameters, and systematically extrapolating results as the bare scalar mass approaches infinity. This reformulation resolves longstanding technical obstacles and offers a straightforward implementation protocol for digital quantum simulation of the Kogut-Susskind Hamiltonian with exponential speedup compared to classical methods and previously known quantum methods, modulo standard assumptions made also for the original Kogut-Susskind approach. We emphasize that the present work establishes this equivalence using classical Euclidean Monte Carlo; the exponential speedup itself is a property of quantum simulation of the orbifold Hamiltonian established in earlier work, which the equivalence shown here lets one inherit for the Kogut-Susskind Hamiltonian.
↳ quant-phhep-lathep-phhep-th+19 citations
11
Unwinding the rare $Ω$ sector: Fragmentation of fully charmed baryons from HL-LHC to FCC
Francesco Giovanni Celiberto🇪🇸
By adopting a hadron-structure-oriented approach, we present and discuss the release of the novel OMG3Q1.0 set of collinear fragmentation functions for fully charmed, rare $Ω$ baryons. Our methodology combines diquark-like proxy model inputs for both charm-quark and gluon channels, calculated at the initial energy scales, with a DGLAP evolution that ensures a consistent treatment of heavy-quark thresholds, following directly from the HF-NRevo scheme. We complement our work with a phenomenological study of NLL/NLO $^{+}$ resummed $Ω_{3 c}$ plus jet distributions using (sym)JETHAD at the HL-LHC and the future FCC. Unraveling the production mechanisms of rare, yet-unobserved hadrons, as provided by the OMG3Q1.0 functions, stands as a key asset for deepening our understanding of QCD at future high-energy hadron colliders.
↳ hep-phhep-exnucl-exnucl-thPRD(2025)·15 citations
12
Photon-induced production of the exotic charged charmonium-like state $Z_{c} (3900)$ off nuclear targets and its internal structure
E. Ya. Paryev🇷🇺
In this paper, we investigate the possibility to study the famous charged charmonium-like state $Z_{c} (3900)$ production off nuclear targets and its properties in inclusive photon-induced reactions near the kinematic threshold within the collision model based on the nuclear spectral function. The model accounts for its charged components $Z_{c} (3900)^{\pm}$ production in direct photon-nucleon interactions as well as three different popular scenarios for their internal structures: compact tetraquarks, molecules of the two open-charm mesons and mixtures of both of them. We calculate the absolute and relative excitation functions for production of $Z_{c} (3900)^{\pm}$ mesons on $^{12}$ C and $^{184}$ W target nuclei at initial photon energies of 9.0-17.5 GeV, the absolute momentum differential cross sections and their ratios for the $Z_{c} (3900)^{\pm}$ production off these target nuclei at laboratory polar angles of 0 $^{\circ}$ -10 $^{\circ}$ and at photon energy of 14 GeV as well as the A-dependences of the ratios of the total cross sections for $Z_{c} (3900)^{\pm}$ production at photon energy of 14 GeV within the adopted scenarios for the $Z_{c} (3900)^{\pm}$ internal structures. We demonstrate that the absolute and relative observables considered show a certain sensitivity to the $Z_{c} (3900)^{\pm}$ internal structures which are by far the best known. Hence, they might be useful for the determination of these structures -- the issue which has attracted much attention in the hadron physics community -- from the comparison of them with the experimental data from the future high-precision experiments at the CEBAF facility.
↳ hep-phhep-exnucl-exnucl-thNPA(2025)·2 citations
13
Thermal dilepton production within conformal viscous Gubser flow
Lakshmi J. Naik🇮🇳 · V. Sreekanth🇮🇳
By employing the Gubser solutions of causal relativistic second-order Israel-Stewart hydrodynamics, we study the thermal dilepton production from heavy-ion collisions, considering the transverse expansion of the viscous hot QCD medium along with longitudinal boost-invariance. We analyze the evolution of the temperature and shear stress profiles of the QCD matter under Gubser flow for different values of the associated parameter $q$ (inverse length scale). We study the dilepton production using leading order Born rates from QGP and hadronic sectors under Gubser geometry. Viscous modified dilepton rate is calculated using the first-order Chapman-Enskog (CE) like non-equilibrium correction of the particle distribution function. Our study indicates that lower values of $q$ result in the enhancement of the emitted dilepton spectra. We also determine the effective temperature of the hot QCD medium from the inverse slope of transverse mass spectra, for different $q$ . We find that the effective temperature determined from the dilepton spectra for a smaller system to be higher. Further, we compare the strength of CE like and Grad's viscous correction to the ideal dilepton spectra and find that CE type viscous corrections are well behaved compared to that of Grad's in the presence of transverse flow.
↳ hep-phnucl-thEPJC(2025)·4 citations
14
Application range of perfect spin hydrodynamics
Zbigniew Drogosz🇵🇱 · Wojciech Florkowski🇵🇱 · Valeriya Mykhaylova🇵🇱
The application range of perfect spin hydrodynamics is studied in two cases: one based on the classical spin description and the other using a quantum spin density matrix (Wigner function). Different forms of the conditions connecting the components of the spin polarization tensor, particle mass, temperature, and hydrodynamic flow are introduced, and their mutual relations are explained. The results obtained are important for practical applications of spin hydrodynamics to model heavy-ion collisions.
↳ hep-phnucl-thPRD(2025)·7 citations
15
Toward extracting scattering phase shift from integrated correlation functions IV: Coulomb corrections
Peng Guo🇺🇸 · Frank X. Lee🇺🇸
The formalism developed in Refs.~\cite{Guo:2023ecc,Guo:2024zal,Guo:2024pvt} that relates the integrated correlation functions for a trapped system to the infinite volume scattering phase shifts through a weighted integral is further extended to include Coulomb interaction between charged particles. The original formalism cannot be applied due to different divergent asymptotic behavior resulting from the long-range nature of the Coulomb force. We show that a modified formula in which the difference of integrated correlation functions between particles interacting with Coulomb plus short-range interaction and with Coulomb interaction alone is free of divergence, and has rapid approach to its infinite volume limit. Using an exactly solvable model, we demonstrate that the short-range potential scattering phase shifts can be reliably extracted from the formula in the presence of Coulomb interaction.
↳ hep-latcond-mat.othercond-mat.quant-gashep-ph+1PRD(2025)·6 citations
16
Anisotropy effects on heavy quark dynamics in Gribov modified gluon plasma
Sumit🇨🇳 · Jai Prakash🇨🇳 · Santosh Kumar Das🇮🇳 · Najmul Haque🇮🇳
In the early stages of relativistic heavy-ion collisions, the quark-gluon plasma momentum distribution is anisotropic, leading to instabilities driven by chromomagnetic plasma modes. In this work, we consider the anisotropic momentum distribution of the medium constituents to investigate its effects on charm and bottom quark dynamics using the nonperturbative Gribov resummation approach within the Fokker-Planck equation framework. Specifically, we investigate the impact of nonperturbative effects and weak anisotropies on the heavy-quark transport coefficients, accounting for the angular dependence of the anisotropy vector relative to the heavy-quark motion direction. Furthermore, the calculated drag and diffusion coefficients are used to estimate heavy-quark energy loss and the nuclear modification factor, accounting for both elastic and inelastic collisions. Our findings indicate that momentum anisotropy, angular dependence, and nonperturbative effects-captured through the scattering amplitudes-play a significant role in determining the transport properties of heavy quarks.
↳ hep-phnucl-thJ.Phys.G(2026)·2 citations

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