Nuclear Theory·nucl-th

Thursday·September 4, 2025

19 papers—9 primary·10 cross-listed

01
Towards Precise Simulations and Inference for the Neutron EDM
Skyler Degenkolb🇩🇪 · Luigi Favaro🇧🇪 · Peter Fierlinger🇩🇪 · Jennifer Franz🇩🇪 · Husain Manasawala🇩🇪 · Tilman Plehn🇩🇪
Precision measurements of neutron properties, like its permanent electric dipole moment, rely on understanding complex experimental setups in detail. We show how the properties of stored and transported ultracold neutron ensembles can be simulated reliably. In a second step, we illustrate how they can be used for simulation-based inference of the parameters associated with underlying physics processes such as neutron capture or beta decay. Our proof of principle for simulation-based inference confronts a longstanding challenge with ultracold neutrons: low measurement statistics coupled with a complex apparatus.
nucl-thhep-phnucl-ex0 citations
02
Observation of renormalization group invariance in symmetry-restored nuclear lattice effective field theory
Jia-Ai Shi🇨🇳 · Chen-Can Wang🇨🇳 · Bing-Nan Lu🇨🇳
Renormalization group (RG) invariance implies that the predictions of effective field theory are independent of the momentum cutoffs introduced during regularization. Here we report the first systematic verification of RG invariance for realistic nuclear few-body systems within nuclear lattice effective field theory. To restore broken continuum rotational and Galilean symmetries, we employ Galilean-invariance-restoration counterterms and use a soft momentum regulator. We calibrate the two- and three-body next-to-next-to leading order (N $^{2}$ LO) chiral forces using $A \leq 3$ observables and perform precision quantum Monte Carlo calculations to compute the $^{4}$ He binding energy. The predicted energy remains constant across cutoffs from $250$ ~MeV to $400$ ~MeV and agrees well with the experimental value, with discrepancies of order 100 keV. Our results demonstrate the capability of extracting accurate, cutoff-independent predictions within lattice-regulated \textit{ab initio} nuclear theory.
nucl-thhep-latPLB(2026)·3 citations
03
A Study on the Triggering of Nucleonic Direct Urca Processes in Neutron Stars of Specific Masses and Their Hyperon Dependence
Yan Xu🇨🇳 · Yufu Shen🇨🇳 · Qi Yuan🇨🇳 · Xiulin Huang🇨🇳 · Yibo Wang🇨🇳
This work aims to analyze how hyperons affect neutrino radiation properties in nucleonic direct URCA processes, expecting to provide useful references for finding evidence of the existence of hyperons in astronomical observations. This analysis is carried out using the GM1 and NL3 parameter sets under the SU(6) and SU(3) flavor symmetries in the relativistic mean field theory framework. Combined with the inferred mass and radius values of PSRs J1231-1411, J0030+0451, and J0740+6620, our results show that nucleonic direct Urca processes are absent in PSR J1231-1411 due to momentum conservation violation. In hyperon-containing PSR J0030+0451 (NL3 parameter set), the nucleonic direct Urca processes involving $e^{-}$ / $μ^{-}$ would occur. A large inferred mass span induces hyperon fraction variations, affecting neutrino emissivity. If the inferred mass of PSR J0030+0451 exceeds approximately 1.8 $M_{⊙}$ , the neutrino luminosity of the nucleonic direct Urca processes under the SU(3) flavor symmetry remains nearly the same as that in npe $μ$ matter, without depending on hyperons. However, it exhibits an obvious hyperon dependence under the SU(6) spin-flavor symmetry. For hyperon-containing J0740+6620, the nucleonic direct Urca processes under the SU(3) flavor symmetry in GM1 parameter set predicts faster neutrino luminosity decline with hyperonic fraction than npe $μ$ matter, and under the SU(6) spin-flavor symmetry in NL3 parameter set it shows monotonic decreasing trend. The research shows that hyperonic fraction significantly affect the neutrino radiation properties of the nucleonic direct URCA processes in neutron stars. Different-mass pulsars (e.g., PSRs J1231-1411, J0030+0451, J0740+6620) exhibit the distinct nucleonic direct URCA processes behaviors, dependent on inferred masses/radii, parameter sets, and theoretical models.
nucl-thCPC(2026)·1 citation
04
Origin of nucleon mass in the light of PSR J0614-3329 with quark-hadron crossover
Bikai Gao🇯🇵 · Yuk-Kei Kong🇯🇵 · Yong-Liang Ma🇨🇳
The recent NICER observation of PSR J0614-3329, revealing the smallest reliably measured neutron star radius of $R = 10.2 9_{- 0.86}^{+ 1.01}$ km at mass $M = 1.4 4_{- 0.07}^{+ 0.06} M_{⊙}$ , provides an unprecedented constraint on the equation of state of dense matter. We investigate the implications of this measurement for the origin of nucleon mass within the parity doublet model framework, which naturally incorporates both chiral variant and chiral invariant mass components. We construct unified equations of state by employing the parity doublet model with isovector scalar meson $a_{0} (980)$ for hadronic matter up to twice nuclear saturation density, smoothly connected to a Nambu-Jona-Lasinio-type quark model at higher densities through a crossover transition. By systematically varying the chiral invariant mass $m_{0}$ and quark matter parameters, we determine which values simultaneously satisfy all current astrophysical constraints, including gravitational wave observations from GW170817, NICER measurements of several pulsars, and the existence of two-solar-mass neutron stars. The inclusion of PSR J0614-3329 dramatically refines the allowed range of the chiral invariant mass from the previous constraint of $580 MeV ≲ m_{0} ≲ 860 MeV$ to $800 MeV ≲ m_{0} ≲ 860 MeV$ , raising the lower bound by approximately 220 MeV. This result indicates that the chiral invariant mass must constitute at least 85\% of the nucleon mass, challenging the traditional picture of nucleon mass generation through spontaneous chiral symmetry breaking alone and highlighting the importance of gluon condensation and other non-chiral mechanisms.
nucl-thastro-ph.HEhep-phPRD(2025)·13 citations
05
The equation of state for neutron stars with speed of sound constraints via Bayesian inference
Xieyuan Dong🇨🇳 · Hong Shen🇨🇳 · Jinniu Hu🇨🇳 · Ying Zhang🇨🇳
The parametrized equation of state (EOS) of neutron stars is investigated by Bayesian inference method with various constraints from both nuclear physics and modern astronomical observations. The expansion coefficients correspond to the properties of symmetric nuclear matter and the density dependence of the symmetry energy. The empirical values of the symmetry energy at subsaturation density and the density of crust-core phase transition are considered to limit the low-density behavior of EOS, i.e. $L_{sym}$ , while the speed of sound of neutron star matter and mass-radius observations of millisecond pulsars PSR J0030+0451 and PSR J0740+6620 are adopted to eliminate the high-order expansion coefficients, such as $Q_{sat}$ and $Q_{sym}$ . Finally, our analysis reveals that the skewness coefficient $Q_{sat}$ of the energy per nucleon in symmetric nuclear matter (SNM) exhibits the strongest correlation with the speed of sound, constrained to $Q_{sat} = - 69.5 0_{- 31.93}^{+ 16.52} MeV$ , whose uncertainties are much smaller than those of the experiments of heavy-ion collisions. The symmetry energy parameters are determined as follows: slope $L_{sym} = 34.3 2_{- 11.85}^{+ 13.66} MeV$ , curvature $K_{sym} = - 58.4 5_{- 89.46}^{+ 88.47} MeV$ , and skewness $Q_{sym} = 302.2 8_{- 231.89}^{+ 251.62} MeV$ . Additionally, the radii of canonical ( $1.4 M_{⊙}$ ) and massive ( $2.0 M_{⊙}$ ) neutron stars are predicted as $R_{1.4} = 11.8 5_{- 0.15}^{+ 0.06} km$ and $R_{2.0} = 11.4 2_{- 0.35}^{+ 0.23} km$ , respectively, with a maximum mass of $M_{max} = 2.1 2_{- 0.05}^{+ 0.11} M_{⊙}$ . The tidal deformability is $Λ_{1.4} = 303.5 7_{- 45.22}^{+ 47.95}$ at $1.4 M_{⊙}$ , which is consistent with the analysis of the GW170817 event.
nucl-thPRD(2025)·9 citations
06
Suppression of dynamical momentum-space shell by chiral symmetry
Bikai Gao🇯🇵 · Michał Marczenko🇵🇱
We investigate the appearance of quark degrees of freedom in dense isospin-symmetric nuclear matter. We employ the parity doublet model to incorporate chiral dynamics. Specifically, we contrast quarkyonic matter, in which quarks occupy states above the nucleon Fermi surface, with baryquark matter, in which quarks populate states inside the nucleonic Fermi sea. We find that while baryquark matter is generally energetically favored over quarkyonic matter, the self-consistent treatment of the momentum-space shell reveals that purely hadronic matter provides the lowest free energy up to densities well beyond nuclear saturation. Consequently, the contribution of quarks is not relevant within the model's domain of applicability, even though chiral symmetry becomes restored. This demonstrates that the onset of quark degrees of freedom and the restoration of chiral symmetry need not coincide.
nucl-thhep-phPRC(2026)·2 citations
07
Electromagnetic radiation from Quark-Gluon Plasma at finite baryon density
Xiang-Yu Wu🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦 · Jean-François Paquet🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸
Using the Bayesian calibrated iEBE-MUSIC framework, we compute the production of electromagnetic radiation from hot hadronic matter at finite baryon density. Results for thermal photon and thermal dilepton yields are obtained by folding in-medium emission rates with posterior-sampled backgrounds evolved hydrodynamically. We consider different photon sources and analyze the collision-energy dependence of the thermal-to-prompt photon ratio. The sensitivity of the dilepton spectra to the pre-equilibrium stage is explored by considering different initialization procedures. Finally, we examine the impact on dilepton spectra of choosing parameter sets stemming from different Bayesian data analyses.
nucl-thEPJ Web Conf.(2026)·4 citations
08
Bayesian analysis of properties of nuclear matter with the FOPI experimental data
Guojun Wei🇨🇳 · Manzi Nan🇨🇳 · Pengcheng Li🇨🇳 · Yongjia Wang🇨🇳 · Qingfeng Li🇨🇳 · Gaochan Yong🇨🇳 · Fuhu Liu🇨🇳
Based on the ultra-relativistic quantum molecular dynamics (UrQMD) transport model, combined with experimental data of directed flow, elliptic flow, and nuclear stopping power measured by FOPI in $^{197} Au +^{197} Au$ collisions at beam energies ( $E_{l ab}$ ) of 0.25 and 0.4 GeV/nucleon, the incompressibility of the nuclear equation of state $K_{0}$ , the nucleon effective mass $m^{*}$ , and the in-medium correction factor ( $F$ , with respect to free-space values) on the nucleon-nucleon elastic cross sections are studied by Bayesian analysis. It is found that both $m^{*}$ and $F$ can be tightly constrained with the uncertainty $\leq$ 15\%, however, $K_{0}$ cannot be constrained tightly. We deduce $m^{*} / m_{0} = 0.7 8_{- 0.10}^{+ 0.09}$ and $F = 0.7 5_{- 0.07}^{+ 0.08}$ with experimental data at $E_{l ab}$ = 0.25 GeV/nucleon, and the obtained values increased to $m^{*} / m_{0} = 0.8 8_{- 0.03}^{+ 0.03}$ and $F = 0.8 8_{- 0.07}^{+ 0.06}$ at $E_{l ab}$ = 0.4 GeV/nucleon. The obtained results are further verified with rapidity-dependent flow data.
nucl-thPRC(2026)·5 citations
09
Color-superconducting quarkyonic matter
Christoph Gärtlein🇵🇹 · Oleksii Ivanytskyi🇷🇸 · Violetta Sagun🇬🇧 · Ilídio Lopes🇵🇹
We explore the role of color superconductivity in quarkyonic matter under the conditions of color and electric neutrality at $β$ - and strong equilibrium, as relevant for neutron stars. By explicitly incorporating the color-superconducting pairing gap into the phenomenological model of a smooth transition from hadron to quark matter, we extend the known quarkyonic framework to include this essential aspect relevant at high densities. The momentum dependence of the pairing gap, motivated by the running of the QCD coupling and introduced similarly to chiral quark models with nonlocal interaction, is a novel element of the model that is crucial for enabling the simultaneous onset of all color-flavor quark states in the presence of color superconductivity. While asymptotically conformal behavior of the present model is ensured by construction, we demonstrate that reaching the conformal limit in agreement with the predictions of perturbative QCD is provided by the proper momentum dependence of the thickness of the hadron shell in momentum space. We employ the flexible meta-modeling approach to nuclear matter, analyzing the structure of the hadron shell in momentum space and focusing on the effects of color superconductivity in quarkyonic matter. Similar to the effects induced by the onset of the quarkyonic phase, color superconductivity leads to stiffening of the equation of state of the NS matter. This causes a significant impact on observable properties of neutron stars, which are analyzed and compared to recent astrophysical and theoretical constraints. We argue that the developed model of color-superconducting quarkyonic matter provides a new, consistent tool for studying the scenario of smooth quark-hadron transition in NSs.
nucl-thastro-ph.HEhep-phPRD(2026)·8 citations
10
Two-flavor chirally imbalanced quark matter beyond large $N_{c}$
André G. da Silva🇧🇷 · Dyana C. Duarte🇧🇷 · Ricardo L. S. Farias🇧🇷 · Marcus Benghi Pinto🇧🇷 · Rudnei O. Ramos🇧🇷 · William R. Tavares🇧🇷
We investigate a chirally imbalanced medium in the context of the two-flavor Nambu--Jona-Lasinio model using both the large- $N_{c}$ (LN) and beyond large- $N_{c}$ (BLN) approximations. To incorporate BLN effects, we consider the optimized perturbation theory (OPT) to the first nontrivial order, which includes two-loop (exchange) contributions. This procedure allows us to explicitly explore how finite $N_{c}$ corrections affect the thermodynamics as well as the phase diagram of chirally imbalanced quark matter. We then compare the results obtained with a sharp three-dimensional cutoff -- generically referred to as the traditional regularization scheme -- and with an alternative procedure called the medium separation scheme (MSS). In the first case, we observe that the pseudocritical temperature decreases as the chiral chemical potential increases, an effect dubbed inverse chiral catalysis. On the other hand, when considering the MSS regularization, which properly isolates the medium contributions from the vacuum, we find the opposite result. We show that the results obtained with MSS are consistent with well-established LQCD data in both the LN and BLN approximations. Finally, we suggest that to cope with the high-density limit, the standard OPT interpolation prescription must be modified with the inclusion of an extra variational parameter.
↳ hep-phhep-thnucl-thPRD(2025)·6 citations
11
Revisiting the first-order QCD phase transition in dense strong interaction matter
Yi Lu🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳
We revisit the phase structure and thermodynamics of QCD in the low temperature and high density region, where a strong, first-order phase transition is expected beyond the critical end point. By solving the quark gap equation in the continuum QCD approach, we reveal the coexistence of the multi-phases both in the microscopic dynamics of chiral symmetry breaking and also in the thermodynamic observables, which manifests the existence of spinodal decomposition during the first-order QCD phase transitions. We also analyse the interface structure of the co-exist Nambu and Wigner phases in the isothermal process during the first-order transition. In particular, the interface tension and interface entropy density are extracted from the isothermal trajectories, which further allows for an analysis on the formation of nuclear bubble, including the bubble radius and its stability at different temperatures. Our predictions may serve as useful inputs for further investigations in heavy-ion physics or astrophysics research.
↳ hep-phhep-thnucl-th2 citations
12
Lee--Yang edge singularities in Nonlocal Nambu--Jona-Lasinio Model
Zong-shuai Zhang🇨🇳 · Yi Lu🇨🇳 · Yu-xin Liu🇨🇳
We investigate the QCD phase diagram and the associated Lee--Yang edge singularities using the two-flavor nonlocal Nambu--Jona-Lasinio model extended to complex chemical potential. There exists a strong correlation between the chiral phase transition and the structure of the effective potential in the complex order parameter plane, serving as a criterion to differentiate crossover from first-order transitions. Typically, the Lee--Yang edge singularities can be understood as a generalization of the critical end-point (CEP) between crossover and first-order transitions, where the positive Nambu phase and the Wigner phase coalesce. We further analyze the scaling behavior near the CEP by extracting the critical exponent associated with the Lee--Yang singularities. Additionally, we confirm that the extrapolation of the Lee--Yang edge singularity trajectories provides an effective method of determining the CEP location, even at a small real chemical potential. This provides a viable method for exploring regions of the QCD phase diagram that remain inaccessible to lattice QCD.
↳ hep-phhep-thnucl-thPRD(2026)·2 citations
13
The role of the soft scale for $J / ψ$ production in the transverse momentum dependent framework
Marston Copeland🇺🇸 · Sean Fleming🇺🇸 · Reed Hodges🇺🇸
We use vNRQCD to study power corrections in the $v$ expansion due to soft gluon radiation during $J / ψ$ production at small transverse momentum. We categorize four new $J / ψ$ production operators that mediate the transition of perturbatively produced color-octet charm quark/anti-quark pairs to charm quarks in a $^{3} S_{1}^{[1]}$ state via soft gluon emission. We then use Soft Collinear Effective Theory and vNRQCD to derive a factorization theorem for $J / ψ$ production in SIDIS in terms of the gluon transverse momentum dependent (TMD) PDFs in the proton and new objects which we call TMD soft transition functions. We show that the TMD soft transition function leads in the $v$ power-counting with respect to the color-octet TMD shape functions that have been used in previous studies of $J / ψ$ production at small transverse momentum.
↳ hep-phhep-thnucl-th7 citations
14
Kilonovae and Long-duration Gamma-ray Bursts
Marko Ristić🇺🇸 · Brandon L. Barker🇺🇸 · Samuel Cupp🇺🇸 · Axel Gross🇺🇸 · Nicole Lloyd-Ronning🇺🇸 · Oleg Korobkin🇺🇸 · Jonah M. Miller🇺🇸 · Matthew R. Mumpower🇺🇸
Recent detections of kilonova-like emission following long-duration gamma-ray bursts GRB211211A and GRB230307A have been interpreted as originating from the merger of two neutron stars. In this work, we demonstrate that these observations are also consistent with nucleosynthesis originating from a collapsar scenario. Our model accurately predicts the observed optical and infrared light curves using a single weak $r$ -process component. The absence of lanthanide-rich material in our model, consistent with the data, challenges the prevailing interpretation that a red evolution in such transients necessarily indicates the presence of heavy $r$ -process elements.
↳ astro-ph.HEnucl-thApJL(2026)·6 citations
15
Recent progress on charmed hadron interactions from lattice QCD
Yan Lyu🇯🇵
Recent years have witnessed rapid progress in charmed hadron physics, driven by numerous experimental discoveries of exotic states such as $T_{cc}^{+}$ and $P_{c}$ . These findings have highlighted the importance of understanding charmed hadron interactions. With significant advances in theory and computation, lattice QCD has become a reliable tool for studying nonperturbative dynamics of low-energy QCD. In this talk, I review recent lattice QCD studies of charmed hadron interactions, focusing on three representative systems: $D^{*}$ - $D$ , $N$ - $c c ˉ$ , and $Ω_{ccc}$ - $Ω_{ccc}$ .
↳ hep-lathep-phnucl-thPoS(2026)·1 citation
16
Confronting the production mechanisms of nuclei with deuteron and proton-triggered balance functions
Sushanta Tripathy🇸🇪 · Peter Christiansen🇸🇪
In ultra high-energy collisions, nuclei with very low binding energies are not expected to survive the dense and hot final state environment. The traditional view has therefore been that nuclei form via coalescence after the hot environment has dissipated. However, statistical thermal models, where hadrons are produced from a fireball at thermal equilibrium, can describe the relative abundances of light nuclei in pp and heavy-ion collisions at the LHC equally well. In this paper we investigate if balance functions triggered by protons and deuterons can be used to distinguish between the two production mechanisms. The coalescence model is investigated using PYTHIA, while the statistical thermal model is examined using the Thermal FIST package. We find that for both models the same simple relation between proton and deuteron triggered balance functions is applicable. However, there is a striking difference between the two models when the transverse momentum of trigger particles is varied. This dependence offers a promising observable to discriminate between the two production scenarios that goes beyond nuclei production. Furthermore, we find that deuteron-meson balance functions vanish identically for both models due to baryon number conservation and isospin symmetry.
↳ hep-phhep-exnucl-thEPJC(2026)·2 citations
17
Parquet theory for molecular systems: Formalism and static kernel parquet approximation
Antoine Marie · Pierre-François Loos
The $G W$ approximation has become a method of choice for predicting quasiparticle properties in solids and large molecular systems, owing to its favorable accuracy-cost balance. However, its accuracy is the result of a fortuitous cancellation of vertex corrections in the polarizability and self-energy. Hence, when attempting to go beyond $G W$ through inclusion of vertex corrections, the accuracy can deteriorate if this delicate balance is disrupted. In this work, we explore an alternative route that theoretically goes beyond $G W$ : the parquet formalism. Unlike approaches that focus on a single correlation channel, such as the electron-hole channel in $G W$ or the particle-particle channel in $T$ -matrix theory, parquet theory treats all two-body scattering channels on an equal footing. We present the formal structure of the parquet equations, which couple the one-body Green's function, the self-energy, and the two-body vertex. We discuss the approximations necessary to solve this set of equations, the advantages and limitations of this approach, outline its implementation for molecular systems, and assess its accuracy for principal ionization potentials of small molecular systems.
↳ physics.chem-phcond-mat.mtrl-scicond-mat.str-elmath-ph+2J.Chem.Phys.(2025)·1 citation
18
Wigner function of a rigidly rotating and magnetized QED plasma
M. Kiamari🇮🇷 · N. Sadooghi🇮🇷
We determine the Wigner function of a rigidly rotating quantum electrodynamics (QED) plasma in the presence of a constant magnetic field by utilizing the Riemannian normal coordinate approximation, which has been previously proposed in the literature. In this approach, the angular velocity appears only in a specific phase factor, allowing us to compute the point-split fermion two-point correlation function in flat spacetime. To ensure that the fermion correlation function is gauge invariant, we introduce a background gauge field that is fixed to produce a constant magnetic field. Using this Wigner function, we derive the energy-momentum tensor for this medium, which consists of both diagonal and off-diagonal components. By comparing our results with the energy-momentum tensor of an ideal spinful and vortical magnetized fluid, we establish a connection between these components and thermodynamic quantities, such as energy density and different types of pressure. We demonstrate that rigid rotation leads to pressure anisotropy in plasma. Additionally, we compute the associated vector and axial vector currents for this medium, utilizing the previously presented Wigner function. Our results are consistent with existing literature on the subject.
↳ nucl-thgr-qchep-phhep-th3 citations
19
Gluon Condensate via Dirac Spectral Density: IR Phase, Scale Anomaly and IR Decoupling
Ivan Horváth🇺🇸
Quark and gluon scalar densities, $⟨ ψ ˉ ψ ⟩$ and $⟨ F^{2} ⟩$ , reflect the degree of scale-invariance violations in SU(N) gauge theories with fundamental quarks. It is known that $⟨ ψ ˉ ψ ⟩$ can be usefully scale-decomposed via spectral density $ρ (λ)$ of Dirac modes. Here I give such formula for $⟨ F^{2} ⟩$ , which reveals that gluon condensate is a strictly UV quantity. For the recently-found IR phase [1,2], where the infrared (IR) degrees of freedom separate out and become independent of the system's bulk, it implies that $⟨ F^{2} ⟩$ due to this IR part vanishes. Its glue thus doesn't contribute to scale anomaly of the entire system and is, in this sense, scale invariant consistently with the original claim. Associated formulas are used to define IR decoupling of glue, which may serve as an alternative indicator of IR phase transition. Using the simplest form of coherent lattice QCD, we express the effective action of full QCD entirely via Dirac spectral density.
↳ hep-lathep-phhep-thnucl-thPRD(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE