Nuclear Theory·nucl-th

Wednesday·July 16, 2025

15 papers—6 primary·9 cross-listed

01
Polarized Electron Scattering from Light Nuclei at High Energies
Minh Truong Vo🇻🇳 · Vu Dong Tran🇻🇳 · Quang Hung Nguyen🇻🇳
We present a theoretical approach to investigate the scattering of polarized electrons from light nuclei using the multipole expansion for the scattering cross section within the framework of the unified electroweak theory. Scattering processes corresponding to different electron polarizations are analyzed and compared with the unpolarized electron scattering investigated earlier. Besides, the contribution of both polarized and unpolarized terms to the scattering cross section is examined. Numerical calculations for stable $^{6, 7}$ Li and unstable $^{7}$ Be nuclei using the Weinberg-Salam model show that the longitudinal polarization and weak interaction are not explicitly correlated when electrons scatter at $θ ≃ 0^{\circ}$ across all energy scales. A strong correlation emerges at the other scattering angles when the electron energy exceeds 10 GeV. This study provides additional information about nuclear structure and uncovers the role of electron polarization and its correlation with the weak interaction in each process, thus offering a more complete picture of electron-nucleus scattering.
nucl-thNPA(2026)·0 citations
02
Ideal Boson Particle-Antiparticle System at Finite Temperatures
D. Anchishkin🇺🇦 · V. Gnatovskyy🇺🇦 · I. Kondakova🇺🇦
The thermodynamic properties of an ideal bosonic system composed of particles and antiparticles at finite temperatures are examined within the framework of a scalar field model. It is assumed that particle-antiparticle pair creation occurs; however, the system is simultaneously subject to exact charge (isospin) conservation. To implement this constraint, we first consider the system within the Grand Canonical Ensemble and then transform to the Canonical Ensemble using a Legendre transformation. This procedure provides a formally consistent scheme for incorporating the chemical potential at the microscopic level into the Canonical Ensemble framework. To enforce exact conservation of charge (isospin, N_I), we further analyze the thermodynamic properties of the system within the extended Canonical Ensemble, in which the chemical potential becomes a thermodynamic function of the temperature and conserved charge. It is shown that as the temperature decreases, the system undergoes a second-order phase transition to a Bose-Einstein condensate at the critical temperature T_c, but only when the conserved charge is finite, N_I=const \ne 0. In a particle-antiparticle system, the condensate forms exclusively in the component with the dominant particle number density, which determines the excess charge. We demonstrate that the symmetry breaking of the ground state at T=0 results from a first-order phase transition associated with the formation of a Bose-Einstein condensate. Although the transition involves symmetry breaking, it is not spontaneous in the strict field-theoretic sense, but is instead induced by the external injection of particles. Potential experimental signals of Bose-Einstein condensation of pions produced in high-energy nuclear collisions are briefly discussed.
nucl-thhep-phquant-phJ.Phys.G(2025)·0 citations
03
Nucleus-nucleus potentials in the scattering of tightly and weakly bound systems
J. Rangel🇲🇽 · B. Pinheiro🇧🇷 · V.A.B. Zagatto🇧🇷 · J. Lubian🇧🇷 · F.M. Nunes🇺🇸 · L.F. Canto🇧🇷
\begin{description} \item[Background] Fusion reactions play an important role in nucleosynthesis and in applications to society. Yet they remain challenging to model. \item[Purpose] In this work, we investigate the features of the nucleus-nucleus potentials that describe fusion cross sections and compare with those needed for realistic calculations of elastic scattering and other direct-reaction cross sections. \item[Method] We perform coupled-channel calculations for studying elastic and fusion reactions around the Coulomb barrier with a tightly bound projectile ( $^{16}$ O+ $^{144}$ Sm). We also perform Continuum Discretized Coupled Channel calculations to study elastic ( $^{8}$ B+ $^{58}$ Ni) and fusion ( $^{6}$ Li+ $^{198}$ Pt) of loosely bound projectiles in the same energy regime. \item[Results] We contrast the coupled-channel results with those obtained in a single-channel solution with different assumptions for polarization potentials to shed light on the relevant absorption terms required for the two different reaction channels. \item[Conclusions] Our results suggest that different approximations may be required for modeling direct processes and for modeling fusion reactions. \end{description}
nucl-thPRC(2026)·3 citations
04
Giant Dipole Resonance and Related Spin-dependent Excitations
E.B. Balbutsev · I.V. Molodtsova
The time-dependent Hartree-Fock equation is solved by the Wigner Function Moments method taking into account spin degrees of freedom. Energies and reduced transition probabilities of $K^{π} = 0^{-}$ , $1^{-}$ and $2^{-}$ excitations are calculated taking $^{164}$ Dy as an example. The spin degrees of freedom give rise to the electric Spin Dipole Resonance. Its properties and interplay with the Giant Dipole Resonance are investigated. The deformation-induced splitting of the spin $M 2$ resonance is discussed. The results of calculations are compared with the experimental data and other theoretical studies.
nucl-th0 citations
05
Tidal deformability and compactness of neutron stars and massive pulsars from semi-microscopic equations of state
W. M. Seif🇪🇬 · A. S. Hashem🇪🇬
Tidal deformability measures how NS can comfortably deform as a response to an applied tidal field. We use updated constraints on the mass, radius, and tidal deformability of neutron star (NS) objects and pulsars to examine nuclear equations of state (EOS) based on realistic finite-range M3Y nucleon-nucleon interaction, which have been successfully used to describe low- and high-dense nuclear matter (NM). We then employ these EOSs to examine the impact of tidal deformability and compactness of NSs on their structure. We found that the EOSs from CDM3Y-230 to CDM3Y-330 characterized with the saturation incompressibility $K_{0} = 230 - 330$ MeV together yield more limited ranges of tidal deformability and radius for NS objects than their experimentally inferred ranges. For light NS ( $M < M_{⊙}$ ), both $k_{2}$ and $C$ decreases upon decreasing the NS mass, which enhances its tidal deformability. The stiffness of the NS core matter has shown a minor effect on the tidal deformability of such NS ( $M < M_{⊙}$ ). An opposite behavior is obtained as an increase in the tidal Love number but a decrease in the more effective compactness of NS ( $M > M_{⊙}$ ), upon increasing (decreasing) the stiffness of the employed EOS (its mass). This appears as enhanced tidal deformability indicated at a larger radius for NS of stiffer NM and for the lighter NS above $M_{⊙}$ . Unified description of some correlations between tidal deformability, tidal Love number, and NS compactness is provided independent of the details of the considered EOS.
nucl-thAnnals Phys.(2026)·1 citation
06
Bayesian Model Selection and Uncertainty Propagation for Beam Energy Scan Heavy-Ion Collisions
Syed Afrid Jahan🇺🇸 · Hendrik Roch🇺🇸 · Chun Shen🇺🇸
We apply the Bayesian model selection method (based on the Bayes factor) to optimize $s_{NN}$ -dependence in the phenomenological parameters of the (3+1)-dimensional hybrid framework for describing relativistic heavy-ion collisions within the Beam Energy Scan program at the Relativistic Heavy-Ion Collider. The effects of various experimental measurements on the posterior distribution are investigated. We also make model predictions for longitudinal flow decorrelation, rapidity-dependent anisotropic flow and identified particle $v_{0} (p_{T})$ in Au+Au collisions, as well as anisotropic flow coefficients in small systems. Systematic uncertainties in the model predictions are estimated using the variance of the simulation results with a few parameter sets sampled from the posterior distributions.
nucl-thhep-phPRC(2026)·14 citations
07
Oscillations of hypothetical strange stars as an efficient source ultra-high-energy particles
Joanna Jałocha🇵🇱 · Łukasz Bratek🇵🇱
We investigate the dynamical behavior of strange quark matter (SQM) objects, such as stars and planets, when subjected to radial oscillations induced by tidal interactions in stellar systems. Our study demonstrates that SQM objects can efficiently convert mechanical energy into hadronic energy due to the critical mass density at their surfaces of 4.7*10^{14} g/cm^3, below which SQM becomes unstable and decays into photons, hadrons, and leptons. We show that even small-amplitude radial oscillations, with a radius change of as little as 0.1%, can result in significant excitation energies near the surface of SQM stars. This excitation energy is rapidly converted into electromagnetic energy over short timescales approximately 1 ms, potentially leading to observable astrophysical phenomena. Higher amplitude oscillations may cause fragmentation or dissolution of SQM stars, which has important implications for the evolution of binary systems containing SQM objects and the emission of gravitational waves.
↳ astro-ph.HEastro-ph.SRhep-phnucl-thPoS(2025)·0 citations
08
Lattice QCD Study of Positive Parity Dibaryons with Maximal Charm and Strangeness
Navdeep Singh Dhindsa🇮🇳 · Nilmani Mathur🇮🇳 · M. Padmanath🇮🇳
We present the ground-state energy spectra of dibaryons composed of single-flavor quarks, specifically systems with strangeness $S = - 6$ and charm $C = 6$ . Our lattice QCD study is based on $N_{f} = 2 + 1 + 1$ MILC ensembles with highly improved staggered quark (HISQ) sea quarks, spanning four lattice spacings and two spatial volumes. We employ valence quark propagators realized using a relativistic overlap action, evaluate correlation matrices with carefully designed operator bases, and extract reliable ground-state energy estimates in the $S = 0$ and $S = 2$ spin channels. We explore their binding characteristics and interaction dynamics by examining the energy separation between the dibaryon states and the corresponding two-baryon thresholds. These results contribute to a deeper understanding of single-flavor dibaryon states as a function of the quark masses. In the $S = 0$ channel, the $Ω_{ccc}$ - $Ω_{ccc}$ system exhibits a clear signal of a bound state, while the $Ω$ - $Ω$ system lies very close to the threshold, making it difficult to draw definitive conclusions. For $S = 2$ , both systems are found to be unbound.
↳ hep-lathep-exhep-phnucl-thPRD(2025)·5 citations
09
Relativistic and Dynamical Love
Abhishek Hegade K. R.🇺🇸 · K.J. Kwon🇺🇸 · Tejaswi Venumadhav🇺🇸 · Hang Yu🇺🇸 · Nicolás Yunes🇺🇸
Gravitational waves emitted in the late inspiral of binary neutron stars are affected by their tidal deformation. We study the tidal dynamics in full general relativity through matched-asymptotic expansions and prove that the dynamical tidal response can be expanded in a complete set of modes. We further prove that the mode amplitudes satisfy an effective, forced harmonic oscillator equation, which generalizes the overlap-integral formulation of Newtonian gravity. Our relativistic treatment of dynamical tides will avoid systematic biases in future gravitational-wave parameter estimation.
↳ gr-qcastro-ph.HEnucl-thPRL(2026)·16 citations
10
Phenomenological Scaling Relations for SQM Stars with a Massive s-Quark in Gravitationally Strong Magnetic Fields under the Spherical Symmetry Approximation
Łukasz Bratek🇵🇱 · Joanna Jałocha🇵🇱 · Marek Kutschera🇵🇱
Scaling relations with the bag constant parameter are investigated for Strange Quark Matter (SQM) stars in the presence of gravitationally strong magnetic fields minimally coupled with matter, considering both massless and massive strange quark scenarios. Assuming a simple model for such coupling under the approximation of spherical symmetry, a phenomenological scaling formula for the maximum mass of stars is derived as a function of the surface magnetic field and the strange quark mass. This formula is applicable for all formally admissible values of the free parameters, and strict scaling with the bag constant is retained only for a vanishing strange quark mass. As a byproduct of this study, the mathematical structure of the equation of state for the relativistic SQM model with a massive strange quark is revisited without approximations. It is observed that the contribution of the electron term to the energy density cannot be neglected in the theoretical limit of large strange quark masses. Consequently, the maximum mass of SQM stars increases with sufficiently large strange quark mass, contrasting with the behavior observed for low strange quark masses.
↳ astro-ph.HEgr-qcnucl-thPRD(2024)·1 citation
11
Generation of a scalar vortex in a rotational frame
M. Bordag🇷🇺 · D. N. Voskresensky🇷🇺
We consider generation from the vacuum of a scalar charged field in a rigidly rotating frame. Adding an external magnetic field opens the way to Bose condensation of the field. This phenomenon has been studied for external uniform magnetic field occupying the whole volume of the uniformly rotating cylindrical system of finite radius $R$ with a Dirichlet boundary condition imposed on it. Besides continuing this study, we consider the field formed by a flux tube of small radius. We find numerical solutions of the Ginzburg-Pitaevskii equation for the charged scalar field, the critical rotation frequencies, the mean radii and the condensate energies, and compare them with those found in a linearization scheme and with approximate analytical solutions. We show that for the same input parameters the energy of the condensate in the case of the flux tube is lower than in the case of uniform magnetic field in the whole cylinder.
↳ hep-phcond-mat.supr-conhep-thnucl-thPRD(2025)·5 citations
12
Constraints on Kinetic Mixing of Dark Photons from Dilepton Spectra
A. W. Romero Jorge🇩🇪 · E. Bratkovskaya🇩🇪 · T. Song🇩🇪 · L. Sagunski🇩🇪
Dark photons, the hypothetical gauge bosons associated with an additional $U (1)^{'}$ symmetry, can couple to Standard Model particles through a small kinetic mixing parameter $ε$ with the ordinary photon. This mechanism provides a portal between the dark sector and visible matter. In this study, we present a procedure to derive theoretical upper bounds on the kinetic mixing parameter $ε^{2} (M_{U})$ by analyzing dilepton spectra from heavy-ion collisions across a broad energy range, from SIS to LHC energies. Our analysis is based on the microscopic Parton-Hadron-String Dynamics (PHSD) transport approach, which successfully reproduces the measured dilepton spectra in $p + p$ , $p + A$ , and $A + A$ collisions across the same energy range. Besides the dilepton channels resulting from interactions and decays of Standard Model particles (such as mesons and baryons), the PHSD has been extended to include the decay of hypothetical dark photons into dileptons, $U \to e^{+} e^{-}$ . The production of these dark photons occurs via Dalitz decays of $π^{0}$ , $η$ , $ω$ , $η^{'}$ , and $Δ$ resonances; direct decays of $ρ$ , $ω$ , and $ϕ$ ; the kaon mode $K^{+} \to π^{+} U$ ; and thermal $q q ˉ$ annihilation in the quark-gluon plasma. Our results show that high-precision measurements of dilepton spectra in heavy-ion collisions provide a sensitive and competitive probe of dark photons in the MeV to multi-GeV mass range. Furthermore, we quantify the experimental accuracy required to constrain the remaining viable parameter space of kinetic mixing in dark photon scenarios.
↳ hep-phhep-exnucl-exnucl-thPRC(2025)·1 citation
13
Do massive neutrino states really exist?
Danil D. Shelkovkin🇷🇺 · Oleg V. Teryaev🇷🇺
In neutrino physics, while massive states define neutrino masses, the flavor states participating in weak interactions are governed by an off-diagonal mass matrix. This work examines the complete form of this mass matrix, both for a two-flavor toy model and for the general three-flavor case under two distinct mass hierarchies. Using the Monte Carlo method, we estimate the mass matrix parameters and demonstrate how its structure governs the dependence of the interaction cross section on the mass hierarchy (normal vs inverted). This formalism enables the treatment of processes involving neutrino exchange through a non-diagonal propagator, corresponding to a quantum field theory description. Numerical estimates for a local charged-lepton interaction via virtual neutrino exchange yield a ratio of electron-antimuon (lepton flavor violating) to electron-positron cross sections on the order of $1 0^{- 51}$ . Furthermore, the cross section exhibits a fundamental dependence on the lightest neutrino mass, which differs drastically between the two hierarchies. For macroscopic processes, this propagator formalism reproduces the standard neutrino oscillation probability by operating directly with the non-diagonal mass matrix, thereby circumventing the wave-packet formalism and confirming the validity of this approach.
↳ hep-phnucl-th0 citations
14
Nuclear modification factor within a dynamical approach to the complex entropic index
R. Baptista🇧🇷 · L. Q. Rocha🇧🇷 · J. M. C. Pareja🇧🇷 · T. Bhattacharyya🇵🇱 · A. Deppman🇧🇷 · E. Megias🇪🇸 · M. Rybczynski🇵🇱 · G. Wilk🇵🇱 · Z. Wlodarczyk🇵🇱
This work introduces a novel approach to the nuclear deformation factor $R_{AA}$ , grounded in the dynamical effects of the Quark-Gluon Plasma on parton momentum. The approach uses the Blast-Wave method combined with Tsallis Statistics, within the Cooper-Frye freeze-out framework and, by profiting from appropriate simplifications, it gives analytical expressions that describe the observed $R_{AA}$ for two sets of independent measurements at $s = 2.76$ TeV and $s = 5.02$ TeV. A nonlinear dynamical equation describes the dynamics and leads to log-periodic oscillations. With the analytical solutions for that equation, it is possible to link the dynamical approach with the complex- $q$ formalism, which was proposed to describe the log-oscillations observed in experimental data.
↳ hep-phnucl-thEPJA(2025)·4 citations
15
Dihadron Fragmentation and the Confinement Transition in Energy Correlators
Kyle Lee🇺🇸 · Iain Stewart🇺🇸
In this letter, we relate the factorization for $e^{+} e^{-} \to h_{1} h_{2} X$ to the factorization for energy-energy correlators in the collinear limit. This enables us to give a nonperturbative proof of factorization for the energy correlators, relate the energy correlator jet function to transverse-momentum-sensitive dihadron fragmentation functions, and provide a rigorous description of the confinement transition region.
↳ hep-phhep-exnucl-thPRL(2026)·30 citations

Affiliations

first authorsco-authorsvia INSPIRE