Nuclear Theory·nucl-th

Tuesday·July 15, 2025

17 papers—6 primary·11 cross-listed

01
Exact solutions of the nuclear shell-model secular problem: Discrete Non-Orthogonal Shell Model within a Variation After Projection approach
Duy Duc Dao🇫🇷 · Frédéric Nowacki🇫🇷
We investigate the capacity of non-orthogonal many-body expansions in the resolution of the nuclear shell-model secular problem. Exact shell-model solutions are obtained within the variational principle using non-orthogonal Slater determinants as the variational ansatz. These results numerically prove the realization of the Broeckhove-Deumens theorem on the existence of a discrete set of non-orthogonal wavefunctions that exactly span the full shell-model space for low-lying states of interest. With the angular-momentum variation after projection, pairing correlations are shown to be fully captured by Slater determinants as exemplified in the backbending phenomenon occurred in $^{48}$ Cr. The resulting discrete non-orthogonal shell model developed in such variation after projection method is further examined in the case of $^{78}$ Ni, an exotic doubly magic nucleus at the edge of currently feasible diagonalization limits. Its ground state binding energy is shown to converge to a lower value than the largest large-scale shell-model diagonalization ever done by the conventional tridiagonal Lanczos method, revealing an outstanding performance of non-orthogonal Slater determinantal wavefunctions to describe the eigensolutions of shell-model Hamiltonians.
nucl-thPRC(2026)·5 citations
02
Bayesian approach for many-body uncertainties in nuclear structure: Many-body perturbation theory for finite nuclei
Isak Svensson · Alexander Tichai · Kai Hebeler · Achim Schwenk
A comprehensive assessment of theoretical uncertainties defines an important frontier in nuclear structure research. Ideally, theory predictions include uncertainty estimates that take into account truncation effects from both the interactions and the many-body expansion. While the uncertainties from the expansion of the interactions within effective field theories have been studied systematically using Bayesian methods, many-body truncations are usually addressed by expert assessment. In this work we use a Bayesian framework to study many-body uncertainties within many-body perturbation theory applied to finite nuclei. Our framework is applied to a broad range of nuclei across the nuclear chart calculated from two- and three-nucleon interactions based on chiral effective field theory. These developments represent a step towards a more complete and systematic quantification of uncertainties in \emph{ab initio} calculations of nuclei.
nucl-thPRC(2026)·11 citations
03
Pseudo-gauge invariant non-equilibrium density operator
F. Becattini🇮🇹 · C. Hoyos🇪🇸
We obtain a form of the local thermodynamic equilibrium density operator which is invariant under pseudo-gauge transformations of the stress-energy and the spin tensors. This operator is an excellent candidate to describe the dynamics of a system which is assumed to achieve local equilibrium from a pseudo-gauge invariant quantum state, a situation which is believed to occur, for instance, in nuclear collisions at very high energy. As a consequence of pseudo-gauge invariance, the ambiguity affecting the predictions of mean values of observables from a local equilibrium state can be removed.
nucl-thcond-mat.stat-mechhep-thPRL(2026)·13 citations
04
Light and heavy $Λ$ hyperclusters in nuclear matter with relativistic-mean-field models
Cheng-Jun Xia🇨🇳 · Yu-Ting Rong🇨🇳 · Ting-Ting Sun🇨🇳
In the framework of relativistic-mean-field (RMF) models, we investigate the properties of light and heavy $Λ$ hyperclusters emersed in nuclear matter at various densities $n_{gas}$ and proton fractions $Y_{p}$ . In particular, the (hyper)clusters are fixed by solving the Dirac equations imposing the Dirichlet-Neumann boundary condition, while the nuclear matter take constant densities and is treated with Thomas-Fermi approximation. The binding energies of (hyper)clusters decrease with the density of nuclear matter $n_{gas}$ , which eventually become unbound and melt in the presence of nuclear medium, i.e., Mott transition. For light clusters with proton numbers $N_{p} < 4$ , with the addition of $Λ$ hyperons, the binding energies per baryon for $Λ$ hyperclusters become smaller and decrease faster with $n_{gas}$ due to the weaker $N$ - $Λ$ attraction. For heavy clusters with $N_{p} \geq 4$ , on the contrary, the addition of $Λ$ hyperons increases the stability of (hyper)clusters so that the Mott transition density becomes larger as nucleons occupying higher energy states while $Λ$ hyperons remain in the $1 s_{1/2}$ orbital. The isovector effects on (hyper)clusters in nuclear medium are also identified, where the binding energies for (hyper)clusters with $N_{p} > N_{n}$ ( $N_{p} < N_{n}$ ) increase (decrease) with $Y_{p}$ . For those predicted by nonlinear relativistic density functionals, light (hyper)clusters are destabilized drastically as $n_{gas}$ increases, while the binding energies of heavier (hyper)clusters vary smoothly with $n_{gas}$ . The binding energy shifts of various (hyper)clusters due to the impact of nuclear medium are fitted to an analytical formula, which could be employed to examine the evolutions of (hyper)clusters in both heavy-ion collisions and neutron stars.
nucl-thPRC(2025)·2 citations
05
Proton radioactivity in deformed nuclei with microscopic optical potential: A novel angular-dependent emission mechanism in the nanosecond-lived $^{149}$ Lu
Yin Fan · Sibo Wang · Xiao-Hua Li · Haozhao Liang
We present a theoretical description of proton radioactivity in 149Lu, the most oblate deformed proton emitter known, by combining a deformed microscopic optical potential derived from ab initio nuclear matter calculations with the Wentzel-Kramers-Brillouin penetration probabilities and the assault frequency of the emitted proton estimated through a new harmonic-oscillator-inspired scheme. We predict a novel angular-dependent phenomenon unprecedented in spherical proton emitters: the disappearance of classically allowed regions at small polar angles $(θ \leq 2 1^{\circ})$ . Our framework yields a half-life $T_{1/2} = 46 7_{- 108}^{+ 143}$ ns for 149Lu, in excellent agreement within uncertainties with the experimental value $45 0_{- 100}^{+ 170}$ ns. Deformation analysis rigorously excludes configurations with $∣ β_{2} ∣ \geq 0.32$ . Extensions to 150, 151Lu and their isomers also achieve excellent agreement with experimental half-life data. We further predict 148Lu as another highly oblate $(β_{2} = - 0.166)$ proton emitter with a half-life $T_{1/2} = 4.42$ ns. This work validates deformed microscopic optical potentials as a robust predictive tool for drip-line proton emitters and provides quantitative evidence for deformation effects in exotic decays.
nucl-thnucl-exPRC(2026)·2 citations
06
Composition of scalar mesons and their effects on nuclear matter properties in an extended linear sigma model
Yao Ma🇨🇳 · Yong-Liang Ma🇨🇳
It has been argued that the iso-scalar and iso-vector mesons play significant roles in nuclear matter and neutron star structures. We improve the extended linear sigma model with baryons, proposed in our previous work, by introducing the flavor structures constructed from antisymmetric tensors of chiral representations to study these physics. The parameter space of this model is refined with well-reproduced nuclear matter properties at saturation density by the lowest order Lagrangian, ensuring consistency with vacuum results, such as $f_{π} \approx 134 MeV$ . The anticipated plateau-like behaviors of the symmetry energy are predicted at intermediate densities, which is crucial for the consistency of GW170817 and the neutron skin thickness of $Pb^{208}$ . Subsequently, neutron star structures are calculated using several parameter sets, and the results for the nuclear matter properties at saturation density align with empirical values. It is found that the neutron star structures are sensitive to the couplings between the iso-vector $a_{0}$ meson and nucleons and the four-vector meson couplings: small values of both are favorable. Meanwhile, nuclear matter properties at saturation density favor larger values of the latter and are not sensitive to the former. This signifies the statistical significance of neutron star observations when obtaining realistic chiral effective field theories or models at various densities. The parameter set favored by neutron star observations also aligns the behavior of the sound velocity with the conformal limit at high densities relevant to cores of massive stars. It is hoped that the results of this work can guide future studies on the relationship between the microscopic symmetry of strong interactions and macroscopic phenomena.
nucl-thastro-ph.HEPRD(2025)·9 citations
07
Theoretical evaluation of decay mode of $^{229 m} Th$ in solid samples
Ryotaro Masuda · Tomoya Naito · Masashi Kaneko · Hiroyuki Kazama · So Hashiba · Kosuke Misawa · Yoshitaka Kasamatsu
The excitation energy of $^{229 m} Th$ is extremely low at $8.4 eV$ ; thus, this isotope exhibits changes in its decay modes depending on the chemical state, specifically the outermost electronic states. However, the reported half-lives of the $γ$ -ray transition are not consistent among the previous experiments. In this study, we investigate the chemical states of $^{229 m} Th$ by density functional theory calculations. Based on these results, we evaluate the relationship between the experimental half-life of each sample and the electronic state of $Th$ . The calculation results indicate that ion trap method, $Ca F_{2}$ model and $Mg F_{2}$ one decay only via the $γ$ -ray transition, whereas $Li Sr Al F_{6}$ one decays via the $γ$ -ray transition and has a possibility of decay via internal conversion and electron bridge.
↳ physics.atom-phcond-mat.othernucl-exnucl-th+1PRResearch(2025)·1 citation
08
Investigating QCD Dynamical Entropy in high-energy nuclear collisions
G. S. Ramos🇧🇷 · L. S. Moriggi🇧🇷 · M.V. T. Machado🇧🇷
In this work, the concept of QCD dynamical entropy is extended to heavy ion systems. This notion of entropy can be understood as a relative entropy and can also be used to estimate the initial entropy density in ultra-relativistic heavy ion collisions. The key quantity used to calculate this entropy is the nuclear unintegrated gluon distribution (nUGD), which provides a transverse momentum probability density. In the numerical analysis, both the geometric scaling phenomenon and the Glauber-Gribov approach have been used to evaluate realistic models for the nUGD. It is shown that the normalization procedure and the geometric scaling property make the dynamical entropy almost independent of the nucleus mass number $A$ . Results are presented for the dynamical entropy density, $d S_{D} / d y$ , in terms of the rapidity.
↳ hep-phhep-exnucl-thPLB(2025)·8 citations
09
Off-shell modifications of the pion generalized parton distributions and transverse momentum dependent parton distributions
Jin-Li Zhang🇨🇳
The off-shell characteristics of pion generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs) are examined within the framework of the Nambu-Jona-Lasinio model. In our previous papers, we separately investigated the properties of on-shell pion GPDs and light-front wave functions. It is particularly intriguing to compare the differences between on-shell and off-shell pion GPDs, which allows us to explore the effects associated with off-shellness. Due to the absence of crossing symmetry, the moments of GPDs also incorporate odd powers of the skewness parameter, resulting in new off-shell form factors. Through our calculations, we derived correction functions that account for modifications in pion GPDs due to off-shell effects. Unlike their on-shell counterparts, certain properties break down in the off-shell scenario; for instance, symmetry properties and polynomiality conditions may no longer hold. Additionally, we evaluate off-shell TMDs and compare them with their on-shell equivalents while also investigating their dependence on $k_{⊥}$ .
↳ hep-phnucl-thCPC(2026)·3 citations
10
Fragmentation of fully heavy tetraquarks: The TQ4Q1.1 functions as a case study
Francesco Giovanni Celiberto🇪🇸
We extend the study of exotic matter formation via the TQ4Q1.1 set of collinear, variable-flavor-number-scheme fragmentation functions for fully charmed or bottomed tetraquarks in three quantum configurations: scalar ( $J^{P C} = 0^{++}$ ), axial vector ( $J^{P C} = 1^{+-}$ ), and tensor ( $J^{P C} = 2^{++}$ ). We adopt single-parton fragmentation at leading power and implement a nonrelativistic Quantum Chromodynamics (NRQCD) factorization scheme tailored to tetraquark Fock-state configurations. Short-distance inputs at the initial scale are modeled using updated calculations for both gluon- and heavy-quark-initiated channels. A threshold-consistent Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution is then applied via the novel Heavy-flavor nonrelativistic-evolution (HF-NRevo) hybrid scheme. We provide the first systematic treatment of uncertainties from nonperturbative color-composite long-distance matrix elements (LDMEs), as well as from perturbative hard-scattering (H-MHOUs) and fragmentation-scale inputs (F-MHOUs), assessed separately and in combination. To support phenomenology, we compute NLL/NLO $^{+}$ cross sections for tetraquark-jet systems at the HL-LHC and FCC within the hybrid collinear and high-energy factorization (HyF) as implemented in (sym)JETHAD, incorporating angular multiplicities as key observables sensitive to high-energy QCD dynamics. We also provide expected event yields based on realistic luminosity scenarios, offering a concrete benchmark for experimental searches. This work connects the investigation of exotic hadrons with state-of-the-art precision QCD.
↳ hep-phhep-exnucl-exnucl-thPRD(2025)·23 citations
11
Decoding Two-Particle States in QCD with Spatial Wavefunctions
Yan Lyu🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Kotaro Murakami🇯🇵 · Takuya Sugiura🇯🇵
A systematic framework for constructing optimized interpolating operators strongly coupled to QCD two-particle states is developed, which is achieved by incorporating inter-hadron spatial wavefunctions. To efficiently implement these operators in lattice QCD, a novel quark smearing technique utilizing noise vectors is proposed. Applied to the $Ω_{ccc} Ω_{ccc}$ system, these optimized operators prove superior to combinations of limited plane-wave operators, enabling the resolution of distinct eigenstates separated by only $\sim 5$ MeV near the threshold $2 m_{Ω_{ccc}} ≃ 9700$ MeV. This exceptional resolving power opens new possibilities for studies of a wide range of hadronic systems in QCD.
↳ hep-lathep-phnucl-thPRD(2026)·3 citations
12
Wavefunction-based operator optimization for two-hadron systems in lattice QCD
Yan Lyu🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Kotaro Murakami🇯🇵 · Takuya Sugiura🇯🇵
A systematic way to constructing optimized interpolating operators for two-hadron systems is developed by incorporating inter-hadron spatial wavefunctions. The wavefunctions can be obtained from an iterative process with an appropriate initial guess. To implement these operators, a novel quark smearing technique utilizing $Z_{3}$ noise vectors is proposed, which allows for effectively incorporating inter-hadron spatial wavefunctions at the source without using all-to-all quark propagators. Proof-of-principle application to the $Ω_{ccc} Ω_{ccc}$ system using physical-point lattice configurations with a large size $L a ≃ 8.1$ ~fm demonstrates that optimized operators outperform combinations of limited plane-wave operators in the variational analysis, enabling clear identification of states around $2 m_{Ω_{ccc}} ≃ 9700$ MeV with the energy gap as narrow as $\sim 5$ MeV. A comparison on correlation functions, effective energies, and HAL QCD potentials between unoptimized operators and optimized operators is given, with a special emphasis on the effects from nearby elastic scattering states. Potential applicability of the optimized operator to various two-hadron systems and its relation to the variational method are also discussed.
↳ hep-lathep-phnucl-thPRD(2026)·4 citations
13
Phase transition and nuclear symmetry energy from neutron star observations: Constraints in light of PSR J0614--3329
Shao-Peng Tang🇨🇳 · Yong-Jia Huang🇨🇳 · Yi-Zhong Fan🇨🇳
The possible occurrence of a first-order hadron-quark phase transition (FOPT) in neutron-star interiors remains an open question. Whether such a transition can be directly tested with improved observations is a key challenge. Here, we incorporate the latest constraints, especially a new NICER radius measurement for PSR J0614--3329, into a nonparametric Gaussian Process (GP) EOS framework that explicitly includes a first-order transition. We find a Bayes factor of $B \approx 2.3$ when comparing models with and without an explicit phase transition, marginally favoring its presence. At $68%$ credibility, the transition onset density $n_{PT}$ is either below $2 n_{s}$ (corresponding to masses $≲ 1 M_{⊙}$ , with density jump $Δ n \sim 0.5 n_{s}$ ) or, more prominently, above $4 n_{s}$ (near the central density of the heaviest NS, with $Δ n \sim 3 n_{s}$ ), where $n_{s}$ represents the nuclear saturation density. In addition, by using symmetry-energy expansion at low densities ( $< 1.1 n_{s}$ ), we infer a slope parameter $L = 40. 2_{- 14.3}^{+ 19.3}$ MeV, in good agreement with nuclear-experiment values. Intriguingly, $L$ correlates positively with the radius difference between $1.4 M_{⊙}$ and $2.0 M_{⊙}$ stars.
↳ astro-ph.HEnucl-thPRD(2025)·23 citations
14
Quark model of nucleon based on an analogy with polaron
S.S. Afonin🇷🇺 · A.V. Tulub🇷🇺
We demonstrate that the polaron theory from solid state physics can serve as an interesting analogue model for non-perturbative QCD, at least in the description of nucleons and related low-energy physics of strong interactions. By drawing explicit analogies between polaron physics, arising for an electron moving in an ionic crystal, and physics of pion-nucleon interactions, certain rules for the "polaron/QCD correspondence" are proposed. In polaron theory, the effective fermion mass as a function of the coupling constant is known both in the weak and strong coupling limits. The conjectured "polaron/QCD correspondence" translates these results into strong interactions. It is then shown how application of these rules leads to unexpectedly good quantitative predictions for the nucleon mass and the pion-nucleon sigma term. The polaron approach also predicts that the quark degrees of freedom in the form of the constituent quark account for one-third of the nucleon mass, consistent with lattice predictions. We discuss possible physical reasons underlying the observed quantitative similarity between polaron physics and non-perturbative QCD.
↳ hep-phcond-mat.supr-conhep-latnucl-thEPJC(2025)·1 citation
15
Stellar properties indicating the presence of hyperons in neutron stars
Andreas Bauswein🇩🇪 · Aristeidis Nikolaidis🇩🇪 · Georgios Lioutas🇩🇪 · Hristijan Kochankovski🇪🇸 · Prasanta Char🇪🇸 · Chiranjib Mondal🇧🇪 · Micaela Oertel🇫🇷 · Laura Tolos🇪🇸 · Nicolas Chamel🇧🇪 · Stephane Goriely🇧🇪
We describe distinctive stellar features indicating the presence of hyperons in neutron stars as compared to purely nucleonic systems. A strongly negative curvature of the mass-radius relation $R (M)$ is characteristic of hyperons, which can be determined from measurements of neutron stars with three different masses. Similarly, a reduced second derivative of the tidal deformability as function of mass \lambda(M) points to hyperonic degrees of freedom in NS matter. The slopes of such curves R(M) and \lambda(M) can distinguish a hyperonic equation of state from purely nucleonic models if they appear increased (decreased for \lambda(M)) relative to the maximum mass of neutron stars.
↳ astro-ph.HEnucl-thPRResearch(2026)·15 citations
16
Generalized Beth-Uhlenbeck approach to the thermodynamics of quark-hadron matter
David Blaschke🇵🇱 · Oleksii Ivanytskyi🇵🇱 · Gerd Röpke🇩🇪
We present a unified approach to the transition from hadronic matter to quark matter where hadrons are treated as bound states of quarks which dissociate at high densities due to quark Pauli blocking. The newly developed approach makes use of a cluster virial expansion formulated in terms of a generalized $Φ$ -derivable approach to multi-quark correlations with bound and continuum states in their spectrum encoded in hadron phase shifts. Our model can be used to obtain thermodynamic functions not only at zero and small chemical potentials, where they are consistent with lattice QCD simulations, but also at large chemical potentials where lattice QCD simulations have the sign problem. By applying a reaction-kinetic criterion for the chemical freeze-out of multi-quark clusters in heavy-ion collisions, we demonstrate that the chemical freeze-out coincides with their Mott transition. The approach can be applied to study the effects of the QCD transition on primordial black hole formation in the early Universe and on hybrid neutron star formation in supernova explosions and binary neutron star mergers.
↳ hep-phnucl-thPoS(2025)·1 citation
17
Signatures of Odd-Parity $s$ -wave $Ξ^{*}$ States in Femtoscopic Correlation Functions
Jia-Xin Lin🇨🇳 · Pablo Encarnación🇪🇸 · Miguel Albaladejo🇪🇸 · Albert Feijoo🇪🇸
We investigate the $Ξ^{*}$ resonances within the molecular picture, where these states are dynamically generated as poles in the unitarized scattering amplitudes arising from the coupled-channel interactions of $K^{*-} Λ$ , $K^{*-} Σ^{0}$ , $ρ^{-} Ξ^{0}$ , $K^{* 0} Σ^{-}$ , $ρ^{0} Ξ^{-}$ , $ω Ξ^{-}$ , and $ϕ Ξ^{-}$ . The interaction kernel is derived from the local hidden gauge formalism, while the unitarization procedure employs a hybrid method that combines cutoff and dimensional regularizations in the evaluation of the loop function. From a detailed spectroscopic analysis, we identify two $S = - 2$ baryon states whose properties are compatible with some of the $Ξ^{*}$ resonances listed in the Review of Particle Physics. To explore their possible experimental signatures, we compute the femtoscopic correlation functions for all the vector-baryon pairs considered in the present study, using realistic estimates of production weights and varying source sizes $R = 1, 1.1, 1.2, 1.3, 1.5$ fm.
↳ hep-phhep-exnucl-thPLB(2026)·5 citations

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