Nuclear Theory·nucl-th

Tuesday·November 4, 2025

20 papers—12 primary·8 cross-listed

01
Automated calculation of spin, isospin branching rules for su(4) irreps
S. Quintero (1) · R. Henao (1) · J. P. Valencia (1) ((1) Institute of Physics, Universidad de Antioquia, Medellín, Colombia)
The open-source Python package, su4-branching, is introduced for the derivation of comprehensive spin S and isospin T branching rules for any SU(4) irreducible representation.The Wigner supermultiplet scheme in nuclear and hadronic physics is based on SU(4) symmetry. However, the community does not have easy access to practical calculations of branching rules for any irreps.Our implementation combines group-theoretical methods with a notebook interface that is easy to use. This lets researchers look at large and complicated SU(4) irreps and check their work.The software produces tables, CSV files, and visual summaries, and it has been tested against both classic and modern reference results. This work enables group-structure investigations in nuclear modeling, particle physics, and quantum chemistry.
nucl-thComput.Phys.Commun.(2026)·0 citations
02
Deformation-driven intruders in light island-of-inversion nuclei
Calvin W. Johnson · Mark A. Caprio · Shwetha L. Vittal
Islands of inversion occur when the nuclear ground state is dominated by intruder configurations, specifically particle-hole excitations across shell gaps, rather than by the naive spherical shell-model expectation of filled shell configurations. Using the realistic and rigorous no-core shell model, we are able to confirm that deformation drives these intruder states in the light halo nuclides $^{11}$ Li and $^{29}$ F. In small model spaces, these deformed intruders lie high in energy with respect to spherical normal states; as the model space size increases, the intruders energetically approach, albeit slowly, the normal states. This provides further strong evidence of the connection between shape deformation/coexistence and islands of inversion, as well demonstrating as the computational challenges in rigorously modeling this phenomenon. Our results also suggest halo states can be strongly deformed and/or strongly mixed with normal spherical states.
nucl-th2 citations
03
Recent progress in global optimizations of covariant energy density functionals
A. V. Afanasjev · B. Osei · A. Dalbah
The recent progress on global optimizations of covariant energy density functionals (CEDFs) and global calculations of binding energies within the covariant density functional theory (CDFT) has been analyzed and reviewed. Recently developed anchor-based optimization approach of Ref. [1] allows global optimizations of CEDFs at a reasonable numerical cost. Moreover, it permits such optimizations in a very large fermionic basis with a proper extrapolation to an infinite one. This allows to accurately estimate global calculation errors due to use of truncated fermionic basis and neglect of some contributions to binding energies (such as total electron binding energy)
nucl-thEPJ Web Conf.(2025)·0 citations
04
Search for dibaryon resonances in the reactions $dd \to dd π π$ and $p d \to p d π π$
Yu.N. Uzikov🇷🇺 · A.A.Temerbayev🇰🇿 · N.T.Tursunbayev🇰🇿
The isoscalar dibaryon resonance $D_{03} (2380)$ , discovered at WASA@COSY in the total cross section of the reaction $p n \to d π^{0} π^{0}$ and in the elastic pn scattering in the energy range corresponding to the invariant mass of the pn system of 2380 MeV, can reveal itself in the $p d \to p d π π$ and $dd \to dd π π$ reactions at higher energies due to deuteron excitation in the $t$ channel. In this paper, the cross sections of these reactions are estimated based on the model of the reaction $p n \to d π^{0} π^{0}$ , proposed earlier by Platonova and Kukulin.
nucl-thnucl-ex0 citations
05
Implication of multimessenger observations on the relativistic mean-field equation of state of dense nuclear matter and skin thickness of nuclei
Rahul Kumar🇮🇳 · Prasanta Char🇪🇸 · Rana Nandi🇮🇳
The composition and properties of infinite nuclear matter under extreme conditions of temperature and pressure remain incompletely understood. In this work, we constrain the equation of state (EoS) of nuclear matter - constructed within the framework of the Relativistic Mean Field (RMF) model - by combining results from chiral effective field theory and multimessenger observations of neutron stars. Using the saturation properties of nuclear matter, we generate a wide ensemble of EoS, which are subsequently constrained within a Bayesian framework. The resulting posterior distributions provide tight bounds on both the saturation parameters and the coupling constants of the RMF model. Our results indicate that the GW170817 event and the latest NICER observation favor a relatively soft EoS, leading to lower crust-core transition densities and thinner neutron star crusts. The radius of a $1.4 M_{⊙}$ neutron star is tightly constrained to $12.50 8_{- 0.241}^{+ 0.257}$ km, while the maximum mass reaches $2.17 4_{- 0.123}^{+ 0.174} M_{⊙}$ . Furthermore, our analysis reveals that the $ω$ - $ρ$ coupling, which governs the density dependence of the symmetry energy, becomes increasingly significant under successive astrophysical constraints. Finally, the predicted neutron skin thickness of $^{48}$ Ca agrees well with the CREX measurement, whereas that of $^{208}$ Pb remains in tension with PREX-II. In contrast to earlier studies, we do not observe a clear correlation between the neutron skin thickness of $^{208}$ Pb and the symmetry energy slope parameter $L$ .
nucl-thhep-ph0 citations
06
High-order cumulants and correlation functions near the critical point from molecular dynamics
Volodymyr A. Kuznietsov🇺🇸 · Roman Poberezhniuk🇺🇸 · Mark I. Gorenstein🇺🇦 · Volker Koch🇺🇸 · Volodymyr Vovchenko🇺🇸
We present a systematic investigation of particle number fluctuations in the crossover region near the critical endpoint of a first-order phase transition using molecular dynamics simulations of the classical Lennard-Jones fluid. We extend our prior studies to third- and fourth-order cumulants in both coordinate- and momentum-space acceptances and integrated correlation functions (factorial cumulants). We find that, even near the critical point, non-Gaussian cumulants equilibrate on time scales comparable to those of the second-order cumulants, but show stronger finite-size effects. The presence of interactions and of the critical point leads to strong deviations of the cumulants from the ideal-gas baseline in coordinate space; these deviations are expected to persist in momentum space in the presence of collective expansion. In particular, the kurtosis becomes strongly negative, $κ σ^{2} ≪ - 1$ , on the crossover side of the critical point. However, this signal is significantly diluted once an efficiency cut used to distinguish protons from baryons is applied, leading to $∣ κ σ^{2} ∣ ≲ 1$ even in the presence of the critical point. We discuss our results in the context of ongoing measurements of proton number cumulants in heavy-ion collisions in RHIC-BES-II.
nucl-thhep-phPRC(2026)·2 citations
07
Large-scale shell-model investigation of $2 ν$ ECEC in $^{132}$ Ba and $^{78}$ Kr
Deepak Patel🇮🇳 · Praveen C. Srivastava🇮🇳
We present a theoretical investigation of two-neutrino double electron capture ( $2 ν$ ECEC) in $^{132}$ Ba and $^{78}$ Kr based on large-scale shell-model calculations. The nuclear matrix elements (NMEs) for the $2 ν$ ECEC process in $^{132}$ Ba and $^{78}$ Kr are calculated using the SN100PN and GWBXG effective interactions, respectively. The reliability of the employed interactions is first examined through a comparison of the calculated and experimental spectroscopic properties of the parent, intermediate, and granddaughter nuclei involved in the decay. We also examine the cumulative contribution of the $2 ν$ ECEC NME with respect to the $1^{+}$ state energies in the intermediate nuclei. The present results provide an updated and improved shell-model estimate of the $2 ν$ ECEC NME and half-life for $^{78}$ Kr relative to earlier studies, and a baseline theoretical prediction for $^{132}$ Ba that may assist future experimental efforts in constraining this rare decay mode.
nucl-thnucl-exEPJA(2026)·0 citations
08
Proton emission systematics along proton drip line
D.S. Delion · A. Pencu
We analyze the chart containing both spontaneous and beta-delayed proton emission processes in terms of the Coulomb parameter, reduced radius and angular momentum ( $χ$ , $ρ$ , $l$ ). We then compare the methods to estimate decay width $Γ$ of a resonant state in a proton mean field, namely the continuity equation for outgoing Gamow states, phase shift analysis of real scattering states and numerical integration of the Schrödinger equation in the complex plane. We show that they provide similar results in the region where it is possible to evaluate the imaginary part of the energy for a resonant (Gamow) state. We then investigate the role of the centrifugal barrier induced by Coulomb interaction and also by proton single particle orbitals. We show that the so-called universal decay law, connecting the logarithm of the monopole reduced width to the fragmentation potential, remains also valid for beta-delayed proton emission processes. This fact allows us to describe experimental data for all proton emission processes in terms of a linear dependence connecting the logarithm of the monopole Coulomb-reduced decay width to the logarithm of the monopole Coulomb penetrability and fragmentation potential within a factor of three for absolute values.
nucl-thPRC(2026)·0 citations
09
Systematics of the chemical freeze-out line in the high baryon density regime explored at SIS100
Emma Lilith Hofmann🇩🇪 · Tom Reichert🇺🇸 · Volodymyr Vovchenko🇺🇸 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
The systematic uncertainties of chemical freeze-out fits at SIS100 energies (Au+Au reactions at $s_{N N} = 3 - 5$ GeV) are studied using UrQMD simulations. Although hadron production in UrQMD does not occur on a sharp chemical freeze-out hyper-surface, the extracted fit quality is shown to be very good. The extracted chemical parameters depend on the selected hadron species as well as the underlying equation of state (EoS) of the matter. Including light nuclei and anti-protons in the fit increases the expected freeze-out temperature, while a stiffer EoS increases the obtained chemical potential. Similarly, the baryon densities extracted by the thermal fits depend on the choice of hadrons as well as the underlying equation of state. These results are important for the upcoming CBM@FAIR physics program and highlight that a degree of caution is advised when one relates the chemical freeze-out curve to features on the QCD phase diagram like the critical endpoint or a possible phase transition.
nucl-thhep-phEur.Phys.J.ST(2026)·0 citations
10
Systematic study of scalar, vector, and mixed density dependencies in relativistic mean-field descriptions of hyperonic matter in neutron stars
Aprajita Shrivastava🇮🇳 · Prasanta Char🇪🇸 · Sakshi Gautam🇮🇳 · Sarmistha Banik🇮🇳
We investigate the equation of state (EOS) of hyperonic neutron star (NS) matter within a density-dependent relativistic mean-field (DDRMF) framework. The effects of scalar, vector, and mixed density dependencies in meson-baryon couplings are systematically examined along with alternative forms of the $ρ$ -meson coupling. Several meson-nucleon parameter sets are explored here for the first time for neutron stars and compared with the standard DD2 EOS. Most new parameterizations produce stiffer EOSs, leading to neutron stars with larger radii and higher tidal deformabilities. However, the inclusion of $Λ$ hyperons softens these EOSs, and the resulting maximum masses still satisfy the two solar mass limits and agree with NICER measurements. These results highlight the importance of exploring alternative density dependencies in constraining dense matter through multi-messenger observations.
nucl-thastro-ph.HE3 citations
11
Thermodynamic nature of upbend resonance and validity of Brink-Axel hypothesis in the low-energy region
L. Tan Phuc · N. Quang Hung · N. Ngoc Anh · N. Dinh Dang
The nature of low-energy enhancement in the radiative strength function (RSF), which is known as the upbend resonance (UBR) and has a crucial role in the description of neutron-captured cross section and stellar nucleosynthesis, is still under debate. The present letter extends the exact thermal pairing plus phonon damping model to explore the microscopic nature of the UBR and its thermodynamic origin over a wide mass range of odd-odd, odd-A, and even-even systems, from $^{44}$ Sc to $^{153}$ Sm, whose experimental RSFs, including the UBRs, are available. The results of our calculations indicate that the UBR originates from non-collective particle-particle and hole-hole excitations with a strength three times stronger than that of the giant dipole resonance. Moreover, our results reveal that the UBR, which emerges only at finite temperatures within the present framework, invalidates the Brink-Axel hypothesis in the very low $E_{γ}$ region. Last but not least, a global relation between the integrated strength of the RSF in the UBR region to that of the total RSF and the mass number is reported, for the first time, within the present study.
nucl-th1 citation
12
Accurate and Efficient Emulation of Proton-Deuteron Scattering via the Reduced Basis Method and Active Learning
Alex Gnech · Xilin Zhang · Christian Drischler · R. J. Furnstahl · Alessandro Grassi · Alejandro Kievsky · Laura E. Marcucci · Michele Viviani
We introduce highly accurate and efficient emulators for proton-deuteron scattering below the deuteron breakup threshold. We explore two different reduced-basis method strategies: one based on the Kohn variational principle and another on Galerkin projections of the underlying system of linear equations. We use the adaptive greedy algorithm previously developed for two-body scattering for optimal selection of high-fidelity training points in the input parameter space. We demonstrate that these emulators reproduce ab initio hyperspherical harmonics calculations of $R$ -matrix elements with remarkable precision, achieving relative errors as low as $1 0^{- 7}$ with a small number of training points, even in regions of strong nonlinear parameter dependence. They also dramatically accelerate the exploration of the scattering predictions in the parameter space, a capability highly desired for calibrating (chiral) three-nucleon forces against scattering measurements. Our formalism can be further generalized to handle nucleon-deuteron scattering above the breakup threshold. These emulator developments will provide valuable tools to accelerate uncertainty quantification and rigorous parameter inference in the study of nuclear forces.
nucl-thhep-phnucl-ex5 citations
13
The $θ$ -term effects on isospin asymmetric hot and dense quark matter
Lei Zhang🇨🇳 · Lu-Meng Liu🇨🇳 · Mei Huang🇨🇳
We investigate the impact of the CP-violating $θ$ term on isospin symmetry breaking in quark matter and compact star properties using a two-flavor Nambu-Jona-Lasinio (NJL) model. By incorporating the $θ$ parameter through the Kobayashi-Maskawa-'t Hooft (KMT) determinant interaction, we derive the thermodynamic potential and gap equations under finite temperature, baryon chemical potential, and isospin chemical potential. At zero temperature and baryon density, $θ$ suppresses conventional chiral ( $σ$ ) and pion ( $π$ ) condensates while promoting pseudo-scalar ( $η$ ) and scalar-isovector ( $δ$ ) condensates, thereby reducing the critical isospin chemical potential $μ_{I}^{crit}$ for spontaneous symmetry breaking. For $θ = π$ , a first-order phase transition emerges at $μ_{I}^{crit} = 0.021$ GeV, accompanied by CP symmetry restoration. Extending the investigation to finite temperature and baryon chemical potential reveals that these $θ$ -term-induced effects persist. Axion effects (modeled via $θ \equiv a / f_{a}$ ) stiffen the equation of state (EOS) of non-strange quark stars, increasing their maximum mass and radii, in agreement with multimessenger constraints from pulsar observations and gravitational wave events. These results establish $θ$ as a critical parameter modulating both the Quantum Chromodynamics (QCD) phase structure and compact star observables.
↳ hep-phnucl-thPRD(2025)·2 citations
14
Energy Correlators from Partons to Hadrons: Unveiling the Dynamics of the Strong Interactions with Archival ALEPH Data
Hannah Bossi🇺🇸 · Yi Chen🇺🇸 · Yu-Chen Chen🇺🇸 · Max Jaarsma🇳🇱 · Yibei Li🇩🇪 · Jingyu Zhang🇺🇸 · Ian Moult🇺🇸 · Wouter Waalewijn🇳🇱 · Hua Xing Zhu🇨🇳 · Anthony Badea🇺🇸 · Austin Baty🇺🇸 · Christopher McGinn🇺🇸 and 3 other authors
Quantum Chromodynamics (QCD) is a remarkably rich theory exhibiting numerous emergent degrees of freedom, from flux tubes to hadrons. Their description in terms of the underlying quarks and gluons of the QCD Lagrangian remains a central challenge of modern physics. Colliders offer a unique opportunity to probe these phenomena experimentally: high energy partons produced from the QCD vacuum excite these emergent degrees, imprinting their dynamics in correlations in asymptotic energy flux. Decoding these correlations requires measurements with exceptional angular resolution, beyond that achieved in previous measurements. Recent progress has enabled precision calculations of energy flux on charged particles alone, allowing data-theory comparisons for measurements using high resolution tracking detectors. In this Letter, we resurrect thirty-year-old data from the ALEPH tracker, and perform a high angular resolution measurement of the two-point correlation of energy flux, probing QCD over three orders of magnitude in scale in a single measurement. Our measurement unveils for the first time the full spectrum of the correlator, including light-ray quasi-particle states, flux-tube excitations, and their transitions into confined hadrons. We compare our measurement with record precision theoretical predictions, achieving percent level agreement, and revealing interesting new phenomena in the confinement transitions. More broadly, we highlight the immense potential of this newly unlocked archival data set, the so called "recycling frontier", and emphasize synergies with ongoing and future collider experiments.
↳ hep-phhep-exhep-thnucl-ex+131 citations
15
Hadronic scattering in (1+1)D SU(2) lattice gauge theory from tensor networks
João Barata🇨🇭 · Juan Hormaza🇨🇴 · Zhong-Bo Kang🇺🇸 · Wenyang Qian🇪🇸
We present a first real-time study of hadronic scattering in a (1+1)-dimensional SU(2) lattice gauge theory with fundamental fermions using tensor-network techniques. Working in the gaugeless Hamiltonian formulation -- where the gauge field is exactly integrated out and no truncation of the electric flux is required -- we investigate scattering processes across sectors of fixed global baryon number $B = 0, 1, 2$ . These correspond respectively to meson-meson, meson-baryon, and baryon-baryon collisions. At strong coupling, the $B = 0$ and $B = 2$ channels exhibit predominantly elastic dynamics closely resembling those of the U(1) Schwinger model. In contrast, the mixed $B = 1$ sector shows qualitatively new behavior: meson and baryon wave packets become entangled during the collision, and depending on their initial kinematics, the slower state becomes spatially delocalized while the faster one propagates ballistically. We characterize these processes through local observables, entanglement entropy, and the information-lattice, which together reveal how correlations build up and relax during the interaction. Our results establish a first benchmark for non-Abelian real-time scattering from first principles and open the path toward quantum-simulation studies of baryon-number dynamics and inelastic processes in gauge theories.
↳ hep-lathep-phnucl-thquant-phJHEP(2026)·14 citations
16
Empirical Reconstruction of the JSNS $^{2}$ KDAR $ν_{μ}$ - $^{12}$ C Missing-Energy Spectrum with a Two-Ex-Gaussian and Generalized-Tail Model
Kyung Kwang Joo🇰🇷 · Jubin Park🇰🇷 · Minkyu Lee🇰🇷 · Myung-Ki Cheoun🇰🇷
Recent analyses of the JSNS $^{2}$ monoenergetic $ν_{μ}$ scattering on $^{12}$ C at 235.5~MeV have compared the measured missing-energy spectrum with several nuclear models, including \textsc{NuWro}, \textsc{GiBUU}, and RMF+Achilles. While these models reproduce the overall peak position, their respective $χ^{2}$ values of $35.5$ , $176.8$ , and $58.1$ indicate that none can simultaneously describe the spectral width and the high-energy tail, reflecting limitations in the treatment of binding energy, two-particle--two-hole (2p-2h) excitations, and final-state interactions (FSI). To address these discrepancies, we introduce an empirical yet physically motivated representation of the spectrum based on two exponentially modified Gaussian (ex-Gaussian) components for p- and s-shell knockout and a generalized power-exponential continuum term describing multinucleon and FSI-induced strength. The fit reproduces the JSNS $^{2}$ data within the fitted energy range with $χ^{2} = 8.0$ for 6 degrees of freedom. yielding parameters that quantify asymmetric broadening of the s-shell while preserving a narrow quasielastic p-shell response. This compact model demonstrates that a minimal empirical framework can capture key features of the nuclear response and provides a useful reference for phenomenological comparisons and future studies of quasielastic and 2p-2h dynamics in the few-hundred-MeV regime.
↳ hep-phnucl-th0 citations
17
In-medium mass shifts of $B_{c}^{(*)}, B_{s}^{(*)}$ and $D_{s}^{(*)}$ mesons
K. Tsushima🇧🇷 · S.L.P.G. Beres🇧🇷 · G.N. Zeminiani🇧🇷
We present our predictions for the Lorentz scalar mass shifts of two-flavored heavy mesons, $B_{c}^{(*)}, B_{s}^{(*)}$ and $D_{s}^{(*)}$ in symmetric nuclear matter. The in-medium mass shifts are estimated by evaluating the lowest order one-loop self-energies of the mesons based on a flavor-SU(5) effective Lagrangian approach. In-medium properties necessary for the estimates are calculated by the quark-meson coupling (QMC) model. The enhanced self-energies of the mesons in symmetric nuclear matter relative to those in free space, yield the negative mass shifts of these mesons.
↳ hep-phhep-exhep-latnucl-ex+1EPJ Web Conf.(2026)·0 citations
18
Three-dimensional sizes and shapes of pion emission in heavy-ion collisions
Daniel Kincses🇭🇺 · Emese Arpasi🇭🇺 · Laszlo Kovacs🇭🇺 · Marton Nagy🇭🇺 · Mate Csanad🇭🇺
In the era of precision measurements in high-energy heavy-ion physics, there is an increasing expectation towards phenomenological and theoretical studies to provide a better description of data. In recent years, multiple experiments have confirmed through two-pion Bose-Einstein correlation measurements that the shape of the two-pion pair source can be well described by Levy-stable distributions. However, direct comparisons of new phenomenological results with the data are still needed to understand the underlying phenomena and learn more about the nature of pion emission. In this paper, we present a three-dimensional analysis of the two-pion source in Monte-Carlo simulations of Au+Au collisions at 200 GeV per nucleon collision energy, and discuss a detailed comparison with the most recent centrality-dependent measurements from the PHENIX Collaboration.
↳ nucl-exhep-phnucl-thEPJC(2026)·5 citations
19
Skewness-dependent moments of the pion GPD from nonlocal quark-bilinear correlators
Xiang Gao🇺🇸 · Swagato Mukherjee🇺🇸 · Qi Shi🇺🇸 · Fei Yao🇺🇸 · Yong Zhao🇺🇸
We present lattice QCD calculations of the odd Mellin moments of pion valence-quark generalized parton distribution (GPD) up to fifth order, $⟨ x^{4} ⟩$ , and for the skewness range $[- 0.33, 0]$ using operator product expansion of bilocal quark-bilinear operators. The calculations are performed on an ensemble with lattice spacing $a = 0.04 fm$ and valence pion mass $300$ $MeV$ , employing boosted pion states with momenta up to 2.428 GeV and momentum transfers reaching 2.748 GeV $^{2}$ . We employ ratio-scheme renormalization and next-to-leading-logarithmic resummed perturbative matching. At zero skewness, our results are consistent with previous lattice studies. By combining matrix elements at multiple values of skewness and momentum transfer, skewness-dependent moments are obtained through simultaneous polynomiality-constrained fits.
↳ hep-lathep-phnucl-exnucl-thPRD(2026)·14 citations
20
Uncertainties in the production of iron-group nuclides in core-collapse supernovae from Monte Carlo variations of reaction rates
Nobuya Nishimura · Carla Froehlich · Thomas Rauscher
Core-collapse supernovae, occurring at the end of massive star evolution, produce heavy elements, including those in the iron peak. Although the explosion mechanism is not yet fully understood, theoretical models can reproduce optical observations and observed elemental abundances. However, many nuclear reaction rates involved in explosive nucleosynthesis have large uncertainties, impacting the reliability of abundance predictions. To address this, we have previously developed a Monte Carlo-based nucleosynthesis code that accounts for reaction rate uncertainties and has been applied to nucleosynthesis processes beyond iron. Our framework is also well suited for studying explosive nucleosynthesis in supernovae. In this paper, we investigate 1D explosion models using the "PUSH method", focusing on progenitors with varying metallicities and initial masses around $M_{ZAMS} = 16 M_{⊙}$ . Detailed post-process nucleosynthesis calculations and Monte Carlo analyses are used to explore the effects of reaction rate uncertainties and to identify key reaction rates in explosive nucleosynthesis. We find that many reactions have little impact on the production of iron-group nuclei, as these elements are primarily synthesized in the nuclear statistical equilibrium. However, we identify a few "key reactions" that significantly influence the production of radioactive nuclei, which may affect astrophysical observables. In particular, for the production of $^{44}$ Ti, we confirm that several traditionally studied nuclear reactions have a strong impact. However, determining a single reaction rate is insufficient to draw a definitive conclusion.
↳ astro-ph.SRnucl-exnucl-thMNRAS(2026)·1 citation

Affiliations

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