Nuclear Theory·nucl-th

Friday·August 7, 2026

17 papers—3 primary·14 cross-listed

01
TITAN mass measurements of neutron-rich Cs, Ba and r-process lanthanide abundances
T.-H. Yeh · J.D. Cardona · Y. Wang · J. Ash · B. Ashrafkhani · I. Belosovic · J. Bergmann · E. Dunling · L. Egoriti · G. Gelinas · G. Gwinner · Z. Hockenbery and 17 other authors
We present measurements for the masses of five neutron-rich isotopes, $^{149 - 151}$ Cs and $^{151, 152}$ Ba, probed for the first time by TITAN at TRIUMF with time-of-flight measurement techniques. We propagate these masses to the nuclear reaction and decay data required for the simulation of the rapid neutron capture process (r-process) nucleosynthesis in neutron star mergers. We show that these neutron-rich masses affect the abundance predictions near mass number $A \sim 148 - 152$ corresponding to lanthanide element abundances at $Z = 60, 62$ and $63$ . We demonstrate that these new TITAN masses smooth out the odd-even effect in isotopic abundance predictions near $A \sim 150$ in both fission cycling astrophysical conditions and conditions that do not reach actinides. We further show that these new masses adjust how fission fragments settle into place when forming the final abundances, and consider the effect on comparisons with stellar abundance ratios such as [Ag/Eu], [Sm/Eu], and [Nd/Eu].
nucl-thnucl-ex0 citations
02
Quark matter at finite temperature and proto-quark stars with the axion effects in SU(3) Nambu-Jona-Lasinio model
Peng-Cheng Chu🇨🇳 · Jiao-Jiao Wang🇨🇳 · Ke Liu🇨🇳 · Peng Wu🇨🇳 · Yu-Heng Liu · He Liu🇨🇳 · Hong-Ming Liu🇨🇳 · Xiao-Hua Li🇨🇳 · Min Ju🇨🇳 · Xu-Hao Wu🇨🇳 · Ying Zhou🇨🇳
We investigate the thermodynamical properties of strange quark matter (SQM) and proto-quark stars (PQSs) within the SU(3) Nambu-Jona-Lasinio (NJL) model at finite temperature, specifically incorporating the effects of axion fields and vector interactions. Our results demonstrate that these interactions significantly influence the equation of state (EoS), constituent quark masses, entropy density, and the maximum star mass of PQSs at the isentropic stages along the star evolution line. Furthermore, we reveal a distinct thermodynamic signature in the early evolution: the presence of trapped neutrinos leads to a substantial increase in electron number density while simultaneously suppressing the core temperature compared to the neutrino-free case. These findings may highlight the crucial role of the axion effects, flavor-dependent vector interactions, and particle composition in determining the observable properties of compact stars at finite temperature.
nucl-th0 citations
03
Benchmarking electromagnetic observables in angular-momentum projected Hartree-Fock
Raul Bernal-Gonzalez · Calvin W. Johnson
We benchmark electromagnetic transitions and moments (electric quadrupole and magnetic dipole) in angular-momentum projected-after-variation Hartree-Fock calculations against full configuration-interaction diagonalization results in a shell model basis. For such a simple approximation we find reasonably good agreement, including for many odd- $A$ and odd-odd nuclides. As previous work on excitation spectra found, results are frequently improved in cases with shape coexistence. Here we considered select cases from the $s d$ - and $p f$ -valences spaces. While electric quadrupole moments and transitions are, as one might expect, frequently (though not always) well reproduced, especially in even-even nuclides, magnetic dipole moments and transitions are overall better than expected. This continues the benchmarking of projected Hartree-Fock as a simple yet effective alternative to full configuration-interaction as well as an underlying foundation for many other many-body methods.
nucl-th0 citations
04
Quarkoniumlike states above open-flavor thresholds in Born-Oppenheimer EFT
Nora Brambilla🇩🇪 · Roberto Bruschini🇩🇪 · Abhishek Mohapatra🇮🇳 · Fang-Zheng Peng🇩🇪 · Tommaso Scirpa🇩🇪
Many quarkoniumlike states have been observed above open-flavor thresholds, but their organization and internal structure remain unsettled. We study the isoscalar hidden-charm and hidden-bottom sectors in Born--Oppenheimer effective field theory (BOEFT), between the spin--isospin averaged $S + S$ and $S + P$ thresholds. At leading order, heavy-quark spin decouples, and the quarkonium static potential mixes through string breaking with the lowest tetraquark/open-flavor BO potentials of the same quantum numbers. These potentials are constrained by QCD symmetries, their short- and long-distance behavior, and lattice-QCD data. The only calibrated parameter is the lowest $1^{--}$ adjoint meson mass, fixed from the shallow multiplet associated with the $χ_{c 1} (3872)$ . Using $T$ -matrix, $K$ -matrix, and complex-scaling methods, we determine bound states and resonance poles, their masses, pole widths from the included nonstrange $S + S$ channels, normalized pole couplings, and prescription-dependent quarkonium--open-flavor composition measures. Uncoupled hybrid BOEFT multiplets are included as reference levels. The spectrum exhibits a common heavy-quark-spin-symmetry multiplet organization. Most poles are predominantly quarkonium resonances localized at short distances, with the largest open-flavor components closest to threshold. The same equations also generate shallow, spatially extended, open-flavor-dominated states with molecular long-distance characteristics. Their binding energies, radii, and small quarkonium components are highly sensitive to the adjoint meson mass, whereas the higher spectrum is more stable. Together with the hybrid reference levels, the spectrum provides multiplet assignments for most candidates. States not naturally accommodated point to the need for hidden-strange and $S + P$ tetraquark/open-flavor BO sectors and for hybrid--tetraquark and hybrid--quarkonium mixings.
↳ hep-phhep-exhep-latnucl-th1 citation
05
Direct versus resolved photons in DPS in photoproduction on proton and nuclei
B. Blok🇩🇪 · R. Segev🇩🇪
We study the process of double parton scattering (DPS) associated with the photoproduction at a future Electron-Ion collider (EIC) and HERA. We show that in the case of the resolved photon the 1 to 2 processes lead, even at small transverse momenta of the hard processes , to the increase of the DPS by a factor of order 1.6 in the significant part of the phase space, relative to the predictions of the mean field based models . Moreover we study the kinematic region where direct photon contribution is dominant and show it s boundaries for charm and light quark jets. For charmed jets we see that the relevant region is $x_{γ} \geq 0.2 - 0.4$ . This region is even enhanced if we consider the photoproduction on the nuclei.
↳ hep-phhep-exnucl-exnucl-th0 citations
06
Quantum-information fingerprints of partial dynamical symmetry in the interacting boson model
Dhritimalya Roy🇮🇳
Partial dynamical symmetry (PDS) is an algebraic structure in which a prescribed symmetry is neither exact nor completely broken: a subset of eigenstates keeps good quantum numbers and remains solvable while the rest of the spectrum mixes. PDS is currently identified from spectroscopic data, band-head energies, level systematics, and $B (E 2)$ ratios. We ask whether it also has a purely structural signature in the eigenstates, and find that it does, though not in the magnitude of entanglement. The natural diagnostic is the variance of a symmetry Casimir, the label variance $\Var \C [G]$ , which we show coincides with a block-coherence entropy and a block impurity: all three vanish exactly when a state carries a single irreducible-representation label. Resolved state by state, this quantity is zero on the solvable subset and of order $N^{2}$ on the mixed states, at stable symmetry points and at Leviatan's first- and second-order critical points, where it takes two distinct forms set by the order of the transition. The magnitude of bipartite entanglement, by contrast, does not separate solvable from mixed states and drifts even where the labels are exact. We anchor the analysis in $^{168}$ Er, connect the block purity to the ``purity/coherence'' language of the quasi-dynamical-symmetry literature, and show the label variance is uncorrelated with multipartite entanglement and with magic. Finally we encode the model on a qubit register and prepare its solvable and mixed eigenstates variationally, as a step toward evaluating the diagnostic on a quantum device.
↳ quant-phnucl-exnucl-th0 citations
07
A large size of the pion-like excitations in the stringy fluid above $T_{c h}$ is model independent and required by current algebra
L. Ya. Glozman
Multiple lattice evidences support the existence of a confining but chirally symmetric stringy fluid regime of QCD above the chiral symmetry restoration temperature at T_{ch} ~ 155 MeV. This regime is characterized by an approximate chiral spin symmetry and its extensions which means that the propagating excitations represent the chirally symmetric quarks connected into color singlets by the chromoelectric string. Clear \pi,\pi' peaks above T_{ch} were extracted on the lattice from the spatial and temporal correlators, which become broader with temperature and disappear roughly at $3 T_{c h}$ . The meson-like excitations above T_{ch} were studied within the manifestly confining and chirally symmetric model. It has been demonstrated that the chiral symmetry restoration in the confining regime happens because of Pauli blocking of the levels, required for the existence of the quark condensate, by the thermal quark excitation. The same Pauli blocking leads to a huge swelling of the low-spin mesons above T_{ch} which become infinitely large in the chiral limit. This property should be crucial for the explanation of the high collectivity and a very small mean-free path of the constituents above $T_{c h}$ seen experimentally. Here we demonstrate that the swelling of pions above T_{ch} is a model-independent effect required by current algebra.
↳ hep-phhep-exhep-lathep-th+10 citations
08
Directed Flow of Protons and Deuterons in Xe+Cs(I) Collisions: Preliminary BM@N Data and THESEUS Modeling
M. E. Kozhevnikova🇷🇺 · M. V. Mamaev🇷🇺 · I. A. Zhavoronkova🇷🇺 · A. V. Taranenko🇷🇺 · Yu. B. Ivanov🇷🇺
Preliminary BM@N results on the directed flow ( $v_{1}$ ) of protons and deuterons in Xe+Cs(I) collisions at 3.8 $A$ GeV are presented for the 10-40% centrality interval. The measured rapidity dependence of $v_{1}$ is compared with calculations from the THESEUS event generator, where deuterons are produced thermodynamically on an equal basis with hadrons using a late freeze-out scenario. While THESEUS well describes the proton $v_{1}$ data, it shows a slight but systematic overestimation of the deuteron flow at low and intermediate rapidities. This comparison tests both the collective dynamics of baryon-rich matter and the thermodynamic mechanism of light-nucleus formation at Nuclotron energies.
↳ nucl-exhep-phnucl-th0 citations
09
Separating Equation-of-State Dynamics from Hadronic Rescattering in Low-Mass Dileptons
Apiwit Kittiratpattana🇹🇭 · Ayut Limphirat🇹🇭 · Yupeng Yan🇹🇭 · Christoph Herold🇹🇭
We investigate low-mass dilepton emission as a probe of the QCD equation of state and phase structure within non-equilibrium chiral fluid dynamics, comparing first-order phase-transition and crossover scenarios at $s_{NN} = 2.20 - 6.20$ ~GeV. To disentangle effects of the macroscopic equation-of-state dynamics from conventional hadronic in-medium modifications, the $ρ$ and $ω$ meson self-energies are calculated from the same resonance-driven forward-scattering amplitudes in both scenarios. We find two temporally distinct signatures of the first-order phase transition: an early enhancement in the vector-meson pole region associated with the non-equilibrium evolution through the phase transition, and a later enhancement of the low-mass continuum driven by reheating and the prolonged fireball evolution. Both effects survive integration over the complete space-time evolution, with the pole-mass region retaining the strongest sensitivity to the phase structure. Across the investigated beam energies, the pole-mass excitation function retains a pronounced sensitivity to first-order transition dynamics at low collision energies, identifying this mass region as a promising target for future dilepton beam-energy scans.
↳ hep-phnucl-th0 citations
10
A commutant gate for spectral fitting through symmetry forced degeneracy
Stelios Savva
Learned spectral models fail at symmetry forced degenerate sectors for two distinct reasons. Where symmetry forces levels to coincide exactly, the per level observable one would normally fit is not well defined, since every unit vector of that shared space is an eigenvector; and near a symmetry protected crossing, the eigenvector observable gradient carries a factor 1/(lambda_i - lambda_j) that is genuinely singular as the gap closes. The usual response is to regularize the divergence or threshold the gap, and both carry a real cost: a fixed gap cannot both protect a forced multiplet and keep two genuinely distinct levels apart. We show a different fix, on synthetic operator families with a known symmetry answer key. A gate reads the symmetry structure directly from the observed operators, as the linear commutant of the family, one singular value decomposition nullspace, following the simultaneous block diagonalization of Maehara and Murota. Block identity is read from the centre of that commutant rather than from eigenvalue clustering, which makes the forced versus accidental distinction structural rather than metric, and the objective switches between a projector trace through forced blocks and a per level target elsewhere. Under operator estimation noise the gate classifies correctly to epsilon of about 0.3, where energy clustering already fails by 0.02. Gated fitting reaches the truth at machine precision in both the symmetric and the symmetry breaking regime, in the latter converging to a truth that is a singularity of the ungated objective, and observable bias sits at the noise floor. Validation off the regular representation, where multiplicity and dimension separate, eliminated two defective estimators that all regular representation tests had passed. The demonstrated object is a gated estimator; a full parametric matrix model, with the matrices learned, is the next experiment.
↳ math.NAcs.NAnucl-thphysics.comp-ph0 citations
11
Bayesian Inference of fine-features of dense matter EOS from future high-precision data of neutron star radii
Bao-An Li🇺🇸 · Xavier Grundler🇺🇸 · Wen-Jie Xie🇨🇳 · Nai-Bo Zhang🇨🇳
Future high-precision X-ray and gravitational wave observatories are expected to measure the radii of neutron stars (NSs) with an accuracy better than about 0.1 km. However, it remains unclear what particular aspects of the Equation of State (EOS) and to what precision they will be better constrained. Within a Bayesian framework using a meta-model EOS and mock high-precision NS data, the posterior probability distribution functions (PDFs) of NS matter EOS parameters for both hadronic and quark phases and the transition between them were recently studied. We report here a few highlights of these studies.
↳ astro-ph.HEnucl-exnucl-thEPJ Web Conf.(2026)·1 citation
12
First Results on Nucleon Resonance Electroexcitation Amplitudes from $e p \to e^{'} π^{+} π^{-} p^{'}$ Cross Sections at $W$ from $1.56 - 1.76$ GeV and $Q^{2}$ from $2.0 - 5.0$ GeV $^{2}$
V.I.Mokeev🇺🇸 · P.Achenbach🇺🇸 · V.D.Burkert🇺🇸 · D.S.Carman🇺🇸 · R.W.Gothe🇺🇸 · E.L.Isupov🇷🇺 · K.Joo🇺🇸 · K.Neupane🇺🇸 · Y.Wunderlich🇺🇸
The first results on the electroexcitation amplitudes or the $γ_{v} p N^{*}$ electrocouplings for nucleon resonances ( $N^{*}$ s) in the third resonance region are presented. They were obtained from $π^{+} π^{-} p$ electroproduction differential cross sections measured with the CLAS detector and analyzed using the Jefferson Lab-Moscow State University (JM) reaction model. The analysis covers the invariant mass range of the final-state hadrons $W$ from 1.56 to 1.76~GeV and virtual photon four-momentum squared $Q^{2}$ from 2.0 to 5.0~GeV $^{2}$ . Consistent results on the electroexcitation amplitudes of the $N (1675) 5/ 2^{-}$ and $N (1680) 5/ 2^{+}$ obtained from independent analyses of both $π N$ and $π^{+} π^{-} p$ final states, demonstrate the capability of reaction models to extract the $γ_{v} p N^{*}$ electrocouplings for $N^{*}$ s in the third resonance region. Also, for the first time, the electrocouplings of the $Δ (1700) 3/ 2^{-}$ and $N (1720) 3/ 2^{+}$ , which predominantly decay into $π π N$ final states, have become available for $Q^{2} > 2.0$ ~GeV $^{2}$ . Finally, contributions from a new $N^{'} (1720) 3/ 2^{+}$ baryon state to the $π^{+} π^{-} p$ differential cross sections have been observed for $Q^{2} < 5.0$ ~GeV $^{2}$ . The new results on resonance electrocouplings in the third resonance region offer new opportunities to explore various aspects of the strong QCD regime responsible for the generation of nucleon excited states, in particular, shedding light on the emergence of hadron mass in connection with dynamical chiral symmetry breaking.
↳ nucl-exhep-phnucl-th0 citations
13
Photon-nucleon entanglement in Compton scattering at low and high energies
Yoshitaka Hatta🇺🇸 · Víctor Martínez-Fernández🇫🇷
We study spin-spin entanglement in the final state photon-nucleon system in Compton scattering, both at low energy below the pion threshold and at high energy in perturbative QCD to next-to-leading order. We first establish a no-go theorem showing that, for any spin- $\frac{1}{2}$ target, entanglement cannot be generated in unpolarized Compton scattering if the scattering amplitudes are real. We then consider polarized Compton scattering off the electron, the proton and the neutron. At low energy, we uncover a rich variety of maximally entangled Bell states and their unitary equivalents realized across different regions of the kinematic plane. Interestingly, the proton and neutron targets exhibit distinct patterns of entanglement. In the neutron case, the electric and magnetic polarizabilities dramatically influence the pattern and even the existence of entanglement. This suggests that entanglement can serve as a novel tool for investigating the detailed electromagnetic properties of the nucleons.
↳ hep-phhep-exnucl-exnucl-th+12 citations
14
Influence of effective mass of the relativistic mean field theory on core collapse supernovae and compact objects
Kohsuke Sumiyoshi · Hajime Togashi · Shun Furusawa · Shuying Li · Hong Shen · Ken'ichiro Nakazato · Hideyuki Suzuki
We study the influence of the effective mass in the relativistic mean field (RMF) theory on the properties of the central core of collapse-driven supernovae and the formation of compact objects. Influence of the effective mass has been so far studied within the non-relativistic frameworks. In order to clarify the role of the effective mass in the relativistic frameworks, which is different from non-relativistic ones, we adopt the set of equation of state (EOS) tables using the parameterizations TM1e and TM1m, which have different effective masses but with the same saturation properties, in the RMF theory. We show that choices of the effective mass in supernova matter affect both the stiffness of the EOS through pressure and the thermodynamical behavior through temperature under the RMF frameworks. We explore differences in matter evolution with neutrino emissions by performing a set of numerical simulations of the gravitational collapse and bounce of massive stars and the cooling of the proto-neutron stars. The EOS with large effective mass leads to compact proto-neutron stars and early collapse to black holes with high densities and temperatures due to the softness. It leads to high energy neutrinos in long emission from the proto-neutron star cooling and in short burst from the black hole formation.
↳ astro-ph.HEnucl-th0 citations
15
Three-baryon femtoscopy as an effective 3 $\to$ 3 scattering experiment
ALICE Collaboration
Scattering experiments have long been the gold standard for constraining hadron $-$ hadron interactions, providing direct information on the angular momentum and spin dependence over a wide range of kinematic configurations. However, experimental constraints on three-body dynamics remain limited, specifically for unbound systems and systems involving short-lived hadrons. In this work, the three-proton correlation function is measured in pp collisions at $s = 13.6$ TeV with ALICE at the LHC and presented as a novel approach to access hadronic interactions in three-body systems. A new analysis strategy is employed to isolate the p $-$ p $-$ p contribution to the correlation function by correcting for background channels and experimental effects, and enabling a direct comparison with state-of-the-art three-body continuum calculations. The extracted correlation function provides the first direct access to the isospin $3/2$ three-body system. The measured observable is found to be sensitive to the partial-wave structure of the nucleon $-$ nucleon interaction and indicates that the nuclear interaction acts even at high angular momentum and parity states of the three-body system, revealing an effective long-range attractive component, observed experimentally for the first time in a three-proton continuum system. Hence, three-hadron femtoscopy emerges as an effective 3 $\to$ 3 scattering experiment with three unbound hadrons in initial and final states. The copious production of hyperons at the modern high-energy colliders ensures the possibility of extending such measurements beyond nucleons, opening a new avenue for future precision studies of three-body dynamics in the strangeness sector.
↳ nucl-exhep-exnucl-th0 citations
16
QCD Chiral Crossover Line from Lee-Yang Edge Singularities
Heng-Tong Ding🇨🇳 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Kai-Fan Ye🇨🇳
We propose a universality-based reconstruction of the QCD chiral crossover line from Lee-Yang edge singularities in the complex baryon chemical potential plane. The framework maps lattice-extracted complex Lee-Yang-zero estimates, treated as proxies for edge singularities, to the universal chiral Lee-Yang edge and thereby determines the $μ_{B}$ dependence of both the chiral critical line in the light-quark chiral limit and the pseudo-critical crossover line at physical quark masses. As an illustration, we apply the framework to Lee-Yang-zero estimates recently obtained by the Wuppertal-Budapest collaboration from high-statistics lattice QCD simulations. Without imposing the previously determined small- $μ_{B}$ expansion of the crossover line as input, the reconstructed curvature is consistent with existing continuum lattice-QCD results at small $μ_{B}$ . The fitted chiral-limit transition temperature is also compatible with existing chiral-scaling analyses. These results demonstrate that lattice information on Lee-Yang singularities, combined with universal chiral scaling, provides a quantitatively consistent constraint on the QCD crossover line within the present temperature window and establishes a framework that can be systematically improved with future Lee-Yang-zero determinations.
↳ hep-lathep-phnucl-exnucl-th0 citations
17
The impact of nuclear equations of state on the dynamics and multi-messenger emission of magnetorotational stellar explosions
Andrea Celati (1, 2 and 3)🇮🇹 · Matteo Bugli (4, 5 and 2)🇮🇹 · Luca Del Zanna (1, 2 and 3)🇮🇹 · Marco Cusinato (6 and 4)🇫🇷 · Martin Obergaulinger (6 and 7) ((1) Dipartimento di Fisica e Astronomia, Universita di Firenze, Florence, Italy (2) INAF Osservatorio Astrofisico di Arcetri, Florence, Italy (3) INFN Sezione di Firenze, Florence, Italy (4) Universite Paris-Saclay, Universite Paris Cite, CEA, CNRS, AIM, Gif-sur-Yvette, France (5) Institut d'Astrophysique de Paris, CNRS and Sorbonne Universite, Paris, France (6) Departament d'Astronomia i Astrofisica, Universitat de Valencia, Valencia, Spain (7) Observatori Astronomic, Universitat de Valencia, Valencia, Spain)🇪🇸
The gravitational collapse of massive stars at the end of their life leads to powerful supernova explosions that produce compact objects, regulate the dynamics of host galaxies, and contribute to cosmic chemical evolution. In the presence of fast rotation and strong magnetic fields, such explosions can reach extreme energies, explaining sources such as hypernovae and long gamma-ray bursts. We investigate the impact of variations in the nuclear equation of state (EoS) on magnetorotational explosions and their multimessenger emission, including neutrinos and gravitational waves. Differences in stiffness, composition, and finite-temperature behavior of the EoS affect the collapse, bounce, and jet-launching phases. Using the Aenus-Alcar code, which includes relativistic magnetohydrodynamics, two-moment neutrino transport, neutrino-matter interactions, and general-relativistic corrections, we perform axisymmetric simulations with different EoSs. All models start from the same pre-supernova progenitor with solar metallicity, a zero-age main sequence mass of 20 solar masses, a dipolar magnetic field, and a shellular rotation profile. The different EoSs produce significant variations in explosion dynamics, proto-neutron star properties, ejecta mass, and multimessenger signals. Our results show that magnetorotational core-collapse supernova signatures depend not only on the cold stiffness of the EoS, but also on its thermal and compositional properties, highlighting the importance of combining gravitational-wave and neutrino observations to constrain dense matter physics and the explosion mechanism.
↳ astro-ph.HEastro-ph.SRnucl-th1 citation

Affiliations

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