Nuclear Theory·nucl-th

Tuesday·April 29, 2025

14 papers—10 primary·4 cross-listed

01
Asymmetric warm nuclear matter described by Gogny and Skyrme-version models
Odilon Lourenço🇧🇷 · Mariana Dutra🇧🇷 · Mario Centelles🇪🇸 · Xavier Viñas🇪🇸
In this work, we perform a detailed study of the thermodynamical properties of asymmetric nuclear matter at finite temperatures by means of the Gogny force, with a particular focus on its D1 family. We emphasize the investigation of the liquid-gas phase transition with the respective analysis of phase-coexistence boundaries (binodal sections) and instability regions (spinodal contours). Furthermore, the phenomenon of isospin distillation, intrinsically related to the unstable part of the system, is also described. In order to estimate the impact of the finite range of the nuclear interaction, for each Gogny parametrization we provide a respective zero-range Skyrme version, for which the free parameters of the model are obtained with the aim of reproducing at zero temperature the same saturation density, binding energy, incompressibility, isoscalar effective mass, isovector effective mass, symmetry energy, and symmetry energy slope. As a main result, we verify systematic deviations between the Gogny models and their Skyrme-version models, particularly at higher temperatures, where the Skyrme-version parametrizations exhibit reduced binodal and spinodal regions.
nucl-thhep-phPRC(2025)·0 citations
02
Symmetry Energy Expansion with Strange Dense Matter
Yumu Yang🇺🇸 · Nikolas Cruz Camacho🇺🇸 · Mauricio Hippert🇧🇷 · Jacquelyn Noronha-Hostler🇺🇸
The quantum chromodynamics (QCD) phase diagram at large densities and low temperatures can be probed using both neutron stars and low-energy heavy-ion collisions. Heavy-ion collisions are nearly isospin-symmetric systems, whereas neutron stars are highly isospin asymmetric since they are neutron-rich. The symmetry-energy expansion is used to connect these regimes across isospin asymmetry. However, the current symmetry-energy expansion does not account for strange particles. In this work, we include finite strangeness by redefining the isospin-asymmetry parameter and the symmetry-energy expansion in a way that is consistent with QCD SU(3) flavor symmetry. Our new symmetry energy works well beyond typical neutron star central densities and admits a skewness term in the presence of strangeness for the case of weak equilibrium.
nucl-thastro-ph.HEhep-phPRC(2026)·12 citations
03
Isomer production by multi-photon excitation
Weitao Liu · Yuanbin Wu
The multi-photon excitation to the $8$ -eV nuclear isomeric state $^{229 m}$ Th in the direct laser-nucleus interaction is investigated theoretically. We solve the time-dependent Schrödinger equation with the method which allows us to study the $n$ -photon absorption in the nuclear excitation in the direct laser-nucleus interaction. Based on the laser facilities available currently or in the near future, we analyze the impact of the laser parameters on the excitation probability of the multi-photon excitation. The possibilities of the $2$ -, $3$ - and $4$ -photon excitations to the isomeric state $^{229 m}$ Th from the ground state are discussed in details. Our results show the strong impact of the laser intensity and pulse duration on the multi-photon excitation probability. The onset of high-order effects in the multi-photon excitation in the direct laser-nucleus interaction is also revealed. Our findings open new possibilities to study the multi-photon laser-nucleus interaction in high-power laser facilities.
nucl-thPRC(2025)·3 citations
04
Relativistic four-nucleon calculations with rank-one separable potential
S. Yurev · S. Bondarenko
A solution to the relativistic generalization of the four-particle integral Faddeev-Yakubovsky equation is carried out. Only states with zero orbital angular momentum, $S$ states, are considered in the calculations. A rank-one separable potential for nucleon-nucleon interaction is used to solve the two-nucleon Bethe-Salpeter equation. Calculations are carried out taking into account both "3+1" and "2+2" subchannels in the equation. The system of integral equations is solved by the iteration method and the binding energy of the helium-4 nucleus is found. The calculated results are compared with experimental data and nonrelativistic.
nucl-thPhys.Atom.Nucl.(2025)·0 citations
05
Disentangling effects of nucleon size and nucleus structure in relativistic heavy-ion collisions
Hai-Cheng Wang🇨🇳 · Song-Jie Li🇨🇳 · Jun Xu🇨🇳 · Zhong-Zhou Ren🇨🇳
While relativistic heavy-ion collisions become an alternative way of studying nucleus structure, the accurate extraction of nucleus structure could be hampered by the uncertainty of nucleon size, and the latter has attracted people's attention in the past few years. We have compared the impacts of nuclear size and nucleus structure on deformation probes in relativistic heavy-ion collisions based on a multiphase transport (AMPT) model. With increasing nucleon size, the absolute values of the deformation probes are generally reduced due to smeared initial density fluctuations. In heavy systems such as $^{197}$ Au+ $^{197}$ Au collisions, neglecting the nucleon size could underestimate or overestimate significantly the extracted deformation parameter depending on the used deformation probe, while the scaled anisotropic flow and the scaled Pearson correlation coefficient of flow and transverse momentum are good probes of the nucleus deformation rather insensitive to the nucleon size. In small systems such as $^{16}$ O+ $^{16}$ O collisions, the deformation probes are generally more sensitive to the nucleon size than to the nucleus structure, and the transverse momentum fluctuation less sensitive to detailed nucleus structure may serve as a good probe of the nucleon size.
nucl-thhep-exnucl-exPLB(2025)·1 citation
06
Impact of Initial-State Nuclear and Sub-Nucleon Structures on Ultra-Central Puzzle in Heavy Ion Collisions
Qi Wang🇨🇳 · Long-Gang Pang🇨🇳 · Xin-Nian Wang🇨🇳
Hydrodynamic models fail to describe the near-equal $v_{2} / v_{3}$ ratio observed in ultra-central heavy-ion collisions, despite their success in other centrality classes. This discrepancy stems from shear viscosity suppressing higher-order geometric eccentricities, resulting in underestimated $v_{3}$ when using the conventional QGP viscosity coefficient. We explore two initial-state modifications to resolve this puzzle: (1) enforcing a minimum nucleon separation distance to homogenize distributions, and (2) amplifying sub-nucleon structures to reduce initial eccentricity. Using TRENTo initial conditions and 3+1D viscous hydrodynamic model CLVisc, both approaches significantly lower geometric eccentricity, reduce required viscosity, and narrow the $v_{2}$ - $v_{3}$ gap in ultra-central collisions. Our results implicate initial-state nuclear and sub-nucleon structures as critical factors in addressing this puzzle. Resolving it would advance nuclear structure studies and improve precision in extracting QGP transport coefficients (e.g., shear viscosity), bridging microscopic nuclear features to macroscopic quark-gluon plasma properties.
nucl-thhep-ph2 citations
07
A Universal Four-Fermion Formation Framework and Odd-Even Staggering in $α$ Decay
Boshuai Cai · Cenxi Yuan · Chong Qi
Clustering phenomena are common in many physical systems across multiple scales. The nuclear $α$ decay is one of the earliest observed evidences of clustering in quantum systems, yet its formation process remains poorly understood even today. In this letter, we propose a novel global odd-even staggering (OES) feature in $α$ decay, which emerges during the clustering process. To unveil its origin, we develop a Universal Four-Fermion Formation Framework (U4F), which describes the formation of any four-nucleon cluster, such as $α$ particle, from a general microscopic wave function, without assuming the preexistence of clustering or pairing. By combining U4F with the large-scale configuration-interaction approach, we demonstrate that the OES effect in $α$ decay arises from the suppression of clustering correlations due to unpaired nucleons. These findings significantly advance our understanding of cluster formation in nuclei and have important implications for the production of new elements and nuclear synthesis in the universe.
nucl-thSCPMA(2026)·2 citations
08
A "breathing'' octupole $^{208}$ Pb nucleus: resolving the elliptical-to-triangular azimuthal anisotropy puzzle in ultracentral relativistic heavy ion collisions
Hao-jie Xu🇨🇳 · Duoduo Xu🇨🇳 · Shujun Zhao🇨🇳 · Wenbin Zhao🇺🇸 · Huichao Song🇨🇳 · Fuqiang Wang🇺🇸
Relativistic heavy ion collisions provide a unique opportunity to probe the nuclear structure by taking an instantaneous snapshot of the colliding nuclei and converting it into momentum anisotropies of final emitted hadrons. A long-standing puzzle of too large a ratio of the elliptical-to-triangular ( $v_{2}$ -to- $v_{3}$ ) anisotropies in ultracentral $^{208}$ Pb+ $^{208}$ Pb collisions at the Large Hadron Collider(LHC) cannot be solved simply by hydrodynamic simulations with initial conditions containing the spherical or certain deformed shape of $^{208}$ Pb. In this Letter, using the iEBE-VISHNU relativistic viscous hydrodynamic hybrid model simulations with the Trento initial condition, we show that a dynamic octupole deformation--a shape-breathing of $^{208}$ Pb --could potentially solve the $v_{2}$ -to- $v_{3}$ puzzle and simultaneously describe the $v_{3} {4}$ data measured in experiment. Our results highlight the unique capability of capturing transient collective properties of nuclei on yoctosecond ( $1 0^{- 24}$ ~s) timescales, unfeasible with low-energy nuclear reactions.
nucl-thnucl-exPRC(2025)·11 citations
09
Investigation of the formation of superheavy elements with atomic numbers 116 and 120 through $^{50}$ Ti-induced reaction
Bakhodir Kayumov
The synthesis of superheavy elements provides crucial insights into the stability and structure of nuclei at the limits of the periodic table. This study investigates the $^{50}$ Ti $+^{244}$ Pu and $^{50}$ Ti $+^{251}$ Cf reactions as pathways to form superheavy elements (SHEs) 116 (Livermorium) and 120, respectively. Using the dinuclear system model, key parameters such as fusion probability and fusion cross section were calculated. These findings were used to examine neutron emission and survival probability through a statistical approach. The reaction $^{50}$ Ti $+^{244}$ Pu is explored as a continuation of experimental efforts to extend the known isotopic range of element 116, while the $^{50}$ Ti $+^{251}$ Cf reaction represents a frontier for the synthesis of element 120. The role of shell effects, excitation energy, and angular momentum on the production and stability of these nuclei is discussed. The results provide theoretical predictions to guide future experimental efforts aimed at advancing our understanding of the island of stability and the limits of nuclear existence.
nucl-thPRC(2025)·2 citations
10
The shape of differential radial flow $v_{0} (p_{T})$ , not its zero-crossing, carries physical information
Somadutta Bhatta🇺🇸 · Aman Dimri🇺🇸 · Jiangyong Jia🇺🇸
Radial flow, a key collective phenomenon in heavy-ion collisions, manifests itself through event-by-event fluctuations of transverse-momentum ( $p_{T}$ ) spectra. The $p_{T}$ -differential radial flow observable, $v_{0} (p_{T})$ , was introduced to quantify local spectral-shape fluctuations, but it is unavoidably influenced by global multiplicity fluctuations. Using the HIJING model, we show that different event-activity definitions for centrality classification and different spectral normalization schemes generate a constant vertical offset in $v_{0} (p_{T})$ without altering its shape. This offset reflects the impact of residual volume/centrality fluctuations rather than genuine dynamical radial flow fluctuations. Accordingly, only the shape of $v_{0} (p_{T})$ , or equivalently its derivative $d v_{0} (p_{T}) / d p_{T}$ , carries physical information about radial-flow dynamics; its zero crossing does not. Practical implications include the need to vertically align measurements from different experiments before comparison, thereby removing normalization ambiguities when constraining QGP properties.
nucl-thhep-phnucl-exNucl.Sci.Tech.(2026)·7 citations
11
Moat regimes within a $2 + 1$ flavor Polyakov-quark-meson model
Gaoqing Cao🇨🇳
To better understand recent predictions on the moat regime of quantum chromodynamics (QCD) matter, this paper extends the previous work within the two-flavor quark-meson (QM) model to the more realistic $2 + 1$ flavor Polyakov-quark-meson (PQM) model. Mainly, two effects are further taken into account: strange quark and confinement coded through Polyakov loop. Model parameters are chosen to consistently reproduce the pseudocritical temperature from lattice QCD, $T_{C} \sim 156 MeV$ , and the baryon chemical potential at the critical end point (CEP) from FRG-QCD, $μ_{B (CEP)} \sim 635 MeV$ . It is found that the basic features of moat regimes for $σ$ and $π$ mesons remain similar to those from QM model: Moat regimes cover the region where temperature or baryon chemical potential is large; reentrances occur around the critical baryon chemical potential of chiral transition at zero temperature. Thus, the FRG-QCD results can still not be well understood, especially why the CEP should locate at the entrances of moat regimes for $σ$ and $π$ mesons. Nevertheless, some basic features can be understood qualitatively, and it is consistent that the pole energies are increasing functions of momenta in the whole $T - μ_{B}$ plane. The moat regime and pole energy of $K$ mesons are also studied with the features similar.
↳ hep-phnucl-thPRD(2025)·7 citations
12
Different scenarios of dynamical chiral symmetry breaking in the interacting instanton liquid model via flavor symmetry breaking
Yamato Suda🇯🇵 · Daisuke Jido🇯🇵
We investigate a type of dynamical chiral symmetry breaking (D $χ$ SB) for various current quark masses using the interacting instanton liquid model. The type of D $χ$ SB is classified based on the sign of the second derivative of the free energy density with respect to the quark condensate at the origin. We perform numerical simulations of the interacting instanton liquid model with the flavor SU(2) symmetric and (2+1)-flavor quarks. We find that the curvature is negative in the SU(2) case. This means the ordinary type of D $χ$ SB. In contrast, in the (2+1)-flavor case, a positive curvature is observed when the strange quark mass is as small as those of the up and down quarks. This suggests that the anomaly-driven type of D $χ$ SB can occur under the approximate flavor SU(3) symmetry. As the strange quark mass increases, the curvature gradually decreases and becomes negative when the strange quark mass is approximately three times larger than those of the light quarks. This difference can be understood in terms of the 't Hooft vertex which induces a six-quark interaction in the $N_{f} = 3$ case and does a four-quark interaction in the $N_{f} = 2$ case. Our results might indicate that the ratio between the strange and light quark masses plays a crucial role in understanding the microscopic relationship between D $χ$ SB and the anomaly effect.
↳ hep-phnucl-thPRD(2025)·1 citation
13
Properties of $X (3872)$ from hadronic potentials coupled to quarks
Ibuki Terashima · Tetsuo Hyodo
The concept of compositeness is used to quantitatively discuss the hadronic molecular nature in exotic hadrons. In this work, we develop a formulation to explicitly introduce the compact quark state contribution in the hadronic potentials together with the direct four-point interaction. We derive analytic expressions of the compositeness from the effective potential between hadrons when the system has a bound state. Applying this formulation to the $X (3872)$ , we examine the variation of the compositeness with respect to the binding energy, energy of $χ_{c 1} (2 P)$ , cutoff momentum, and strength of the direct $D^{0} D ˉ^{* 0}$ interaction.
↳ hep-phnucl-thPoS(2025)·0 citations
14
$^{208}$ Pb nuclear charge radius revisited: closing the fine-structure-anomaly gap
Zewen Sun · Konstantin Beyer · Zoia A. Mandrykina · Igor A. Valuev · Christoph H. Keitel · Natalia S. Oreshkina
A comprehensive reevaluation of the root-mean-square nuclear charge radius is presented for the doubly magic $^{208}$ Pb extracted from muonic spectroscopy measurements. By integrating rigorous theoretical quantum electrodynamics calculations, state-of-the-art numerical methods, and a systematic reanalysis of the uncertainties, we reduced the long-standing muonic fine-structure anomaly and improved the goodness of fit by a factor of twenty. The resulting value of 5.5062(5)~fm for a Fermi distribution is fairly consistent with the previously reported muonic spectroscopy value, and three standard deviations larger than the commonly used compilation data, which indicates that the current value and its uncertainty could be significantly underestimated. Attributing the remaining discrepancy to theory errors which can not be rigorously calculated we suggest the rms charge radius with reduced model dependence to be 5.5062(17) fm. This work sets an improved benchmark for charge radius extraction in heavy nuclei and paves a path for systematic reevaluations across the nuclear chart.
↳ physics.atom-phnucl-thPRL(2025)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE