Nuclear Theory·nucl-th

Tue·Sep 15, 2026Tuesday·September 15, 2026

12 papers—6 primary·6 cross-listed

01
Nuclear landscape based on point-coupling density functional with localized exchange terms
Y. N. Huang · Q. Zhao🇨🇳 · Y. F. Niu
Nuclear landscape is initially explored in the framework of relativistic Hartree-Bogoliubov theory under the spherical approximation, adopting the newly developed PCF-PK1 density functional. The functional effectively incorporates exchange terms via the Fierz transformation and explicitly includes the tensor coupling. We analyze the limits of the nuclear landscape and nuclear ground state properties including binding energies, charge radii, {\alpha}-decay energies, compared with other functionals and experiment. In the present calculations, 7210 nuclei are predicted to be bound with the root-mean-square deviation of binding energies 7.170 MeV. The removal of spurious shell closure at Z = 58 and 92 is discussed by shell gaps and single-particle spectra. For superheavy nuclei, potential magic numbers beyond 208Pb are studied. The inclusion of the tensor coupling in PCF-PK1 helps restore the pseudospin symmetry, leading to a less pronounced shell closure at Z = 120.
nucl-th0 citations
02
Nuclear mass prediction using bidirectional recurrent neural networks with isotopic and isotonic chain correlations
P. Li🇺🇸 · Y. F. Niu · F. Q. Chen · Z. M. Niu
Nuclear masses are fundamental quantities in nuclear physics, providing essential information for understanding nuclear structure, decay properties, and reaction processes. Here we develop a bidirectional recurrent neural network (Bi-RNN) that naturally incorporates sequential correlations along isotopic and isotonic chains for nuclear mass prediction. The model achieves a root-mean-square (rms) deviation of 78 keV for binding energies of 2339 nuclei with known masses, a 45% improvement over a conventional artificial neural network (ANN) with comparable parameter count. The Bi-RNN also delivers consistent accuracy across different odd-even parity groups and yields an rms of 99 keV for $Q_{β}$ values without explicit training, demonstrating that recurrent correlations encode physically relevant information beyond individual nuclear features. Extrapolation tests on 292 nuclei updated from AME2003 to AME2012 and on 109 nuclei updated from AME2012 to AME2020 reveal that the Bi-RNN maintains stable performance, substantially outperforming WS4, ANN, and earlier AME evaluations. These results demonstrate the power of recurrent architectures in capturing correlations along nuclear chains and suggest Bi-RNN as a robust tool for studying nuclear masses.
nucl-th0 citations
03
Dileptons in heavy-ion collisions
Hendrik van Hees🇩🇪
In this review we give an overview about dileptons as probes for the properties of the strongly interacting hot and dense matter created in heavy-ion collisions at various beam energies. As penetrating probes they leave the fireball unaffected from final-state interactions and thus provide a space-time-evolution weighted average of the in-medium properties of hot and dense QCD matter.
nucl-thhep-ph0 citations
04
Near-thermal state and thermodynamic response of a QCD system in ultra-central heavy-ion collisions
Yu-Shan Mu🇨🇳 · Li Yan🇨🇳 · Xu-Guang Huang🇨🇳
We present a systematic framework to extract QCD thermodynamic properties at finite baryon density from ultra-central heavy-ion collisions, where the impact parameter is nearly zero and volume fluctuations are strongly suppressed. By mapping the measured multi-particle state of each event to an effective homogeneous fireball through the conservation of total energy, total entropy and net baryon number, a near-thermal state with variations is realized from event to event, which allows thermodynamic response relations to be tested. Using STAR Beam Energy Scan data on charged particle multiplicity and net proton fluctuations, we show that the thermalization condition is satisfied within uncertainties across collision energies, validating the interpretation of ultra-central events as small deviations from a thermally equilibrated state. We then generalize the response relations to finite baryon chemical potential, expressing the response coefficients in terms of the speed of sound and susceptibilities. Our results provide a baseline for using ultra-central collisions to probe the QCD equation of state and phase structure, including the search for the critical endpoint.
nucl-thhep-phnucl-ex0 citations
05
Stability and Structural Properties of Hot Quark Stars within Perturbative QCD
Tousif Raza🇺🇸 · Tyler Gorda🇺🇸
The hypothesis of strange quark matter (SQM) and the possible existence of strange stars have been extensively investigated within the thermodynamic bag model, typically employing the free Fermi gas approximation with or without perturbative QCD corrections at zero temperature, where quark confinement is modeled by the bag pressure. In this work, based on the perturbative inclusion of quark mass effects, we develop a thermodynamically consistent equation of state (EOS) for SQM at finite temperature, incorporating perturbative corrections up to $O (α_{s})$ in the strong coupling constant $α_{s}$ while ensuring full adherence to the Maxwell relations. These corrections are essential for accurately describing hot quark stars potentially formed during core-collapse events. We present results for both fixed and running couplings, using a phenomenological model to include the breakdown of the perturbative running of $α_{s}$ at low momenta. Our results demonstrate that incorporating finite-temperature perturbative QCD corrections leads to SQM configurations that fall within the absolute stability window, with equilibrium energies per baryon lying below that of iron, the most tightly bound nucleus. Our EOS supports compact stars with masses exceeding $1.4 M_{⊙}$ (and above $2 M_{⊙}$ for some values of the bag constant), in agreement with current astrophysical constraints from pulsar and gravitational-wave observations.
nucl-thastro-ph.HEhep-ph0 citations
06
Inclusive Neutral-Kaon Photoproduction on the Deuteron
Mutoharoh · Agus Salam · Terry Mart🇮🇩
We report on our study of inclusive neutral-kaon photoproduction on the deuteron, $d (γ, K^{0}) Y N$ , for photon energies between 0.9 and 1.1 GeV. The calculation is performed in the impulse approximation, with the deuteron wave function generated from the Bonn One-Boson-Exchange-Potential in $q$ -space (OBEPQ) within a non-relativistic framework, while the kinematics and the elementary operator are kept relativistic. For the elementary operator we employ a recently developed isobar model that includes high-spin nucleon and $Δ$ resonances and has been constrained by nearly 20,000 data points, and we compare its predictions systematically with those of the Kaon-Maid model. For the first time, the NKS1 and NKS2 data are subjected to a quantitative analysis within a modern elementary production framework. The New Operator provides a considerably better description of the data, whereas Kaon-Maid overestimates the measured cross section by up to a factor of four at the higher photon energies, a discrepancy that can be traced back to its unconstrained $γ n \to K^{0} Λ$ amplitude. We further show that the finite photon-energy and kaon-angle bins of the existing measurements generate a theoretical uncertainty comparable to the difference between the two models, so that a proper comparison with the data requires the calculation to be averaged over the experimental acceptance. A three-dimensional mapping of the cross section over the kaon momentum and angle reveals a narrow quasi-free ridge, accompanied by a second structure associated with the opening of the $Σ$ channels, from which we identify the kinematics most favorable for future measurements. Finally, the tensor target asymmetries are found to be far less sensitive to the elementary operator than the cross section, and therefore probe the nuclear dynamics in a way that is complementary to the cross section.
nucl-thhep-phnucl-ex0 citations
07
Low-energy collective structure of $^{92, 94}$ Zr and $^{94}$ Mo from ( $e, e^{'}$ ) and ( $p, p^{'}$ ) scattering II. Signatures of mixed-symmetry states and origin of collectivity
C. Walz · L.M. Donaldson · P. von Neumann-Cosel🇩🇪 · N. Pietralla🇩🇪 · F.D. Smit
This is the second of two papers discussing a new experimental signature of mixed-symmetry states (MSS) in the vibrational nuclei $^{92, 94}$ Zr and $^{94}$ Mo based on proton and neutron transition densities. Quasiparticle-phonon model calculations for these nuclei are extensively tested by comparison to ground-state properties, energies and moments of excited states, transition probabilities between them, and the momentum transfer dependence in $(e, e^{'})$ and $(p, p^{'})$ reactions. The overall very good agreement permits the extraction of information on the wave functions of the MSS and their fully symmetric (FSS) counterparts. MSS can be identified by a sign change between the leading proton and neutron two-quasiparticle configurations compared to the FSS. Possible candidates for $2^{+}$ , $3^{-}$ , and $4^{+}$ MSS are identified. The modification of proton and neutron transition densities, which can be derived from a combined analysis of inelastic electron and proton scattering, by the sign change provide a new experimental signature of MSS. The collectivity of ground-state excitations of predominantly one-phonon FSS and MSS is generated to a large extent by the coupling to high-lying states forming giant resonances with the same spin and parity.
↳ nucl-exnucl-th0 citations
08
Thermal modifications of the B-meson spectrum
Rachel Horohan D'Arcy🇮🇪 · Benjamin Jäger🇩🇰 · Seyong Kim🇰🇷 · Jon-Ivar Skullerud🇮🇪
A first-principles investigation of heavy-light meson behaviour in hot QCD matter is essential for the interpretation of experimental results associated with open heavy flavour productions in relativistic heavy-ion collision experiments. Using anisotropic lattice ensembles from the FASTSUM collaboration with Nf=2+1 dynamical Wilson-clover fermions at non-zero temperatures, we study the B and B_s spectra at non-zero temperature. We use relativistic light quark propagators, while the b quark propagators are computed with a non-relativistic effective theory (NRQCD). We find that above T_c, thermal effects on the B meson states are more significant than those on the B_s states. Also, our results support the dissolution of the B-meson bound states above T_c.
↳ hep-lathep-phnucl-th0 citations
09
NICER neutron stars with dark energy and dark matter: effects on the inferred equation of state
Nathan Rutherford🇺🇸 · Chanda Prescod-Weinstein🇺🇸 · Anna Watts🇳🇱
[Abridged] In this work, we compare neutron stars where dark energy or dark matter are present in the core, contrasting them against purely baryonic stars with the same central energy density. From this comparison, we find that the dark energy models are more constrained by neutron star observations than the dark matter models, suggesting that neutron stars can place strong constraints on dark energy parameters. We consider four configurations: purely baryonic neutron stars described by a piecewise polytropic (PP) equation of state (EoS), baryonic stars admixed with bosonic or fermionic asymmetric dark matter (ADM) cores, and stars with a dark energy core and baryonic shell, where the dark energy is described by the modified Chaplygin dark fluid (MCDF). Using the masses and radii of PSR J0740 $+$ 6620, PSR J0437 $-$ 4715, and PSR J0030 $+$ 0451, we employ Bayesian inference to investigate how accounting for bosonic/fermionic ADM and MCDF cores affects the inferred neutron star properties. We find that MCDF cores, more than PP and ADM admixed models, substantially broaden neutron star mass-radius and pressure-energy density posterior distributions. Moreover, the MCDF EoS parameters can be tightly constrained. While bosonic and fermionic ADM cores decrease the inferred maximum mass, their posteriors strongly coincide with those of the PP model for ADM mass-fractions $F_{χ} \leq 5%$ . These results demonstrate that current mass-radius observations cannot rule out MCDF cores, but they can constrain the MCDF parameter space to narrow regions. ADM admixed neutron stars, however, remain observationally identical to purely baryonic stars for all explored mass-fractions, even with improved mass-radius uncertainties. This suggests that mass-radius measurements alone are insufficient to detect ADM core inside neutron stars and that independent astrophysical or particle physics probes will be required.
↳ astro-ph.HEastro-ph.COastro-ph.SRhep-ph+10 citations
10
Precision Sum Rule for Nucleon Isovector Polarizabilities and the Proton-Neutron Mass Difference
Xiong-Hui Cao🇨🇳 · Ling-Yun Dai🇨🇳 · Feng-Kun Guo🇨🇳
The precision of the electromagnetic proton-neutron mass difference $δ m_{QED}$ extracted from the Cottingham formula hinges on a subtraction function whose low-energy normalization $S ˉ (0)$ is fixed by the isovector combination of the proton and neutron polarizabilities, $(α_{E 1} - β_{M 1})^{p - n}$ . We derive a dispersive sum rule for this combination in terms of $s$ -channel photoabsorption cross sections and the product of $t$ -channel $γ γ \to π η / K K ˉ_{I_{t} = 1}$ and $π η / K K ˉ_{I_{t} = 1} \to N N ˉ$ amplitudes, without invoking Reggeon dominance. Combining empirical pion-photoproduction multipoles with coupled-channel Muskhelishvili--Omnès representations of the scalar-isovector $π η / K K ˉ$ amplitudes, we obtain $(α_{E 1} - β_{M 1})^{p - n} = - 2.26 (73) \times 1 0^{- 4} fm^{3}$ , fixing its sign and reducing the uncertainty by a factor of 4 compared with the previously known value. This result yields $S ˉ (0) = - 1.76 (61) GeV^{- 2}$ , leading to $δ m_{QED} = 0.7 1_{- 0.06}^{+ 0.03} MeV$ , substantially more precise than previous Cottingham determinations. The negative $S ˉ (0)$ also provides a stringent low-energy test of Reggeon dominance in the subtraction function.
↳ hep-phhep-latnucl-exnucl-th0 citations
11
The $γ Z$ -box correction and its impact on parity-violating deep-inelastic scattering
Balma Duch🇪🇸 · Pere Masjuan🇪🇸 · Hubert Spiesberger🇩🇪
The $γ Z$ -box correction is an important electroweak contribution to precision parity-violation measurements, but its conventional low-energy treatment relies on an ambiguous effective quark-mass prescription. We revisit this correction using a finite-mass calculation that provides a well-defined perturbative contribution without introducing such an auxiliary scale. Applying the result to the Jefferson Lab PVDIS measurement shifts the extracted electron-quark couplings at the $1 0^{- 3}$ level. We discuss the implications of this shift for precision electroweak tests and the need for a consistent separation of perturbative and non-perturbative hadronic contributions.
↳ hep-phnucl-th0 citations
12
Probing gluon saturation through inclusive hadron production in DIS
Carlisle Casuga🇫🇮 · Swaleha Mulani🇵🇱 · Heikki Mäntysaari🇫🇮
We investigate gluon saturation effects in semi-inclusive deep inelastic scattering (SIDIS) at small- $x$ within the Color Glass Condensate framework. We compute the SIDIS cross section at leading order in the dipole picture, expressing it in terms of the dipole-target scattering amplitude. We validate our framework by comparing with the charged hadron spectra measured at HERA. Our predictions for the EIC indicate that saturation effects result in significant nuclear suppression in the SIDIS cross section, and can provide complementary constraints on the initial condition for the Balitsky-Kovchegov evolution extracted from inclusive DIS data. These results demonstrate that SIDIS measurements at the EIC are sensitive to nonlinear QCD dynamics in the saturation regime.
↳ hep-phnucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE