Nuclear Theory·nucl-th

Tuesday·August 25, 2026

22 papers—9 primary·13 cross-listed

01
[Submitted on 22 Aug 2026]
QCD phase transition at finite isospin density and magnetic field within the three-flavor NJL model
Gaoqing Cao
Previously, the QCD phase transition at finite isospin density and magnetic field was explored within the two-flavor Nambu--Jona-Lasinio model. This work extends the study to the more realistic three-flavor case, where not only strange quark contributions but also quark mass splitting in a strong magnetic field are fully taken into account. Adopting the Ginzburg-Landau approximation and the Landau representation for fermion propagators, we re-explore the transitions from the normal chiral symmetry breaking phase to pion superfluidity or rho superconductivity. Unlike the previous study, we project the mesonic fields onto the eigenstates of a charged point particle in a magnetic field and prove that the corresponding self-energies from quark loops are gauge invariant and degenerate with respect to the extra transverse degrees of freedom. However, the numerical results are qualitatively consistent with previous findings: as the isospin chemical potential increases, pion superfluidity is favored at small magnetic fields, while rho superconductivity is favored at large magnetic fields. In the three-flavor model, since the lowest energy of the rho meson increases with stronger magnetic field, the corresponding critical isospin chemical potential also increases with the magnetic field.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2608.21996 [pdf]
0 citations
02
[Submitted on 23 Aug 2026]
Constraining hyperonic relativistic mean-field models with rapidly rotating neutron stars
Gihwan Nam · Prashant Thakur · Yeunhwan Lim · Jeremy W. Holt
Motivated by the recent mass measurement of the black-widow pulsar PSR~J0952 $-$ 0607 with $M = 2.35 \pm 0.11 M_{⊙}$ , we investigate how the masses of heavy, rapidly rotating millisecond pulsars can be used to constrain relativistic mean-field (RMF) models containing hyperonic degrees of freedom. In our approach, hyperons are incorporated following the spin-flavor SU(6) symmetry scheme for the vector-meson couplings. We find that increasing the nonlinear $ω$ -meson vector self-coupling parameter $ζ$ suppresses the hyperon fraction and can alter the onset ordering of the $Σ^{-}$ and $Ξ^{-}$ hyperons. By computing rotating neutron-star configurations at the observed spin frequency $707 Hz$ of PSR~J0952 $-$ 0607, we identify RMF models compatible with this pulsar's observed lower-mass bound. Using an empirical relation for the maximum neutron star mass, the PSR~J0952 $-$ 0607 observational contraint is mapped onto the allowed RMF parameter space in $n_{0}$ , $m^{*}$ , and $ζ$ .
Comments:
19 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2608.22392 [pdf]
0 citations
03
[Submitted on 24 Aug 2026]
Ab initio anatomy of quadrupole correlations in $^{16}$ O and $^{20}$ Ne
Chenrong Ding · Benjamin Bally · Stavros Bofos · Thomas Duguet · Yi Li · Jiangming Yao
Azimuthal hadronic flow measured in ultra-relativistic ion--ion collisions provides a new means of imaging multipole correlations in the ground state of atomic nuclei. Early interpretations largely relied on a classical-rotor picture, in which the measured mean-square elliptic flow is directly related to an intrinsic quadrupole deformation. Atomic nuclei, however, contain additional many-body correlations generated by the Pauli exclusion principle, collective shape fluctuations and non-collective dynamical processes, whose impact on this correspondence has not yet been elucidated. Here, we resolve this issue through an ab initio analysis of $^{16}$ O and $^{20}$ Ne based on chiral nuclear interactions, combining the in-medium similarity renormalization group with the quantum-number-projected generator coordinate method. By successively isolating antisymmetrization, collective rotational and vibrational, and non-collective dynamical correlations, we determine, for the first time, how each component contributes to the mean-square quadrupole eccentricity. We uncover an unexpected compensation among these distinct correlation mechanisms: despite sizable individual contributions, the squared effective quadrupole deformation inferred from the elliptic flow remains close to the square intrinsic deformation of the nucleus. This result provides a microscopic explanation for the surprising success of the classical-rotor approximation and establishes a quantitative foundation for interpreting $^{16}$ O+ $^{16}$ O and $^{20}$ Ne+ $^{20}$ Ne collision data recently collected at the Large Hadron Collider.
Comments:
5+1 pages with 3+3 figures, suggestions and comments are welcome
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2608.22699 [pdf]
0 citations
04
[Submitted on 24 Aug 2026]
Effects of femtoscopic correlations on spin-spin correlation measurements
Bijun Fan · Like Liu · Shusu Shi
Hyperon spin correlations serve as sensitive probes of spin dynamics in high-energy collisions, yet their extraction from weak-decay angular distributions can be contaminated by femtoscopic effects due to quantum statistics and final-state interactions. In this work, we quantitatively assess this contamination for $ΛΛ$ and $Λ Λ ˉ$ pairs using the AMPT model combined with spin-dependent weights from the Lednický--Lyuboshits formalism. Because the singlet and triplet spin configurations contribute differently to the decay-angle distribution, femtoscopic weighting induces an apparent angular modulation, creating a fake correlation signal even when no intrinsic spin correlation is present. We find that the induced bias can become substantial in the low- $q_{inv}$ region, where the combined femtoscopic effect reaches a magnitude comparable to that of the preliminary CMS measurements. Our results establish a framework for evaluating such systematics, highlighting that femtoscopic corrections must be carefully considered in future differential analyses that emphasize the low-relative-momentum region.
Comments:
10 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2608.22707 [pdf]
0 citations
05
[Submitted on 24 Aug 2026]
Nuclear excitation by radiative electron-ion recombination
Jingyan Zhao · Yuanbin Wu
A nuclear excitation mechanism, nuclear excitation by radiative electron-ion recombination (NERER), is put forward theoretically here. NERER is a third-order process that proceeds via a virtual electronic state: an electron recombines into an atomic vacancy of an ion with the simultaneous emission of a real photon and excitation of the nucleus. The photon emission compensates the energy mismatch between the free-bound electronic transition and the nuclear transition energies, thus there is no resonant condition imposed to the incident electron. We develop here the theoretical framework for NERER, and investigate the case of the $8.4$ eV isomeric excitation of $^{229}$ Th for the production of the nuclear clock isomer $^{229 m}$ Th. Our results show that, with the coupling to the inner atomic shells for highly-charged ions, the NERER cross section can exceed the one of the known lower-order process of nuclear excitation by inelastic electron scattering by more than one order of magnitude. Our findings offer a new pathway for nuclear excitation and efficient isomer production, and support further investigations for high-order effects in the interplay between the atomic and nuclear systems.
Comments:
9 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2608.22803 [pdf]
0 citations
06
[Submitted on 24 Aug 2026]
Microscopic study of quasifission dynamics in hot fusion reactions for synthesizing superheavy nuclei with Z = 112-120
Xiangquan Deng · Lu Guo
In the synthesis of superheavy element (SHE) via heavy-ion fusion reactions, quasifission is one of the major factors hindering superheavy nuclei (SHN) formation and the mechanism behind this process is intricate. We investigate dynamics of quasifission in hot fusion reactions synthesizing SHN with Z = 112-120 using microscopic time-dependent Hartree-Fock theory in a total of 18 reactions. Remarkably, the nucleon numbers of heavy fragments distribute closely around certain quantum shells in these reactions, highlighting the crucial role of shell effects in fragment formation. In the reactions with 48Ca, 45Sc, 50Ti and 51V projectiles, the formation of heavy fragment is dominantly driven by the double spherical shells of 208Pb. In contrast, the influence of the double octupole deformed shells at Z = 88 and N = 136 is more pronounced in 54Cr-induced reactions, resulting in a tendency of producing pear-shaped 224Ra heavy fragment. Moreover, in the reaction with a heavier projectile, the colliding system tends to undergo a more rapid quasifission. This may be responsible for significantly reduced fusion probability and synthesis cross section observed in the reactions with projectiles heavier than 48Ca. These results elucidate quasifission mechanisms behind the reactions for synthesizing new SHEs Z = 119 and Z = 120.
Comments:
accepted by Physics Letters B, in press
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2608.22947 [pdf]
0 citations
07
[Submitted on 24 Aug 2026]
Signed Sound-Speed Deformations of BSk24-Anchored Barotropes: Neutron-Star Response
Ioannis Papathanasiou
Background: Localized structure in the equilibrium squared sound speed can affect neutron-star observables, but modifying $d P / d ϵ$ requires thermodynamically consistent reconstruction and assessment over the complete declared domain. Purpose: We quantify the response to positive and negative localized sound-speed changes around a unified BSk24 baseline while keeping the deformation geometry, admission criteria, reconstruction, and fixed-mass comparison protocol fixed. Method: A Gaussian profile with quintic smootherstep activation is added to $c_{s}^{2}$ . Proposals violating $P > 0$ or $0 < c_{s}^{2} \leq 1$ anywhere in the retained domain are rejected before reconstruction. Passing cases are reconstructed as effective cold one-fluid barotropes and evolved with the Tolman-Oppenheimer-Volkoff and tidal equations. Results: The $A = 0$ case reproduces the undeformed control exactly. A localized change produces a persistent pressure offset, relocates the fixed-mass central state, and yields a mass-dependent, nonlinear, sign-asymmetric response. For $A = - 0.8$ and $+ 0.8$ , respectively, $ΔΛ/ Λ_{0} = (- 46.02%, + 35.33%)$ at $1.4 M_{⊙}$ and $(- 63.52%, + 87.17%)$ at $2.0 M_{⊙}$ . The reached stiffened feature remains core connected at the reporting endpoints, whereas the softened feature becomes an off-center shell at high mass. Conclusions: These phenomenological BSk24-anchored effective barotropes illustrate how a local sound-speed intervention propagates through thermodynamic reconstruction and stellar structure. They are not BSk24 predictions or evidence for a microscopic composition or phase transition.
Comments:
19 pages, 10 figures, 6 tables; includes appendices and reproducibility metadata
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2608.23033 [pdf]
0 citations
08
[Submitted on 24 Aug 2026]
Modeling quasielastic lepton-nucleus interactions with ab initio spectral functions from infinite nuclear matter
Alma L. Cavallin · Francesco Marino · Joanna E. Sobczyk
We present a study of quasielastic lepton-nucleus scattering within the local density approximation, using ab initio spectral functions from infinite nuclear matter derived with self-consistent Green's functions theory and interpolated by neural networks. We include final-state interactions in terms of the particle spectral function and investigate the importance and range of validity of this treatment for varying momentum transfer. The performance of the model is tested for inclusive electron scattering on different isospin-symmetric target nuclei, and we present results for $^{12}$ C, $^{16}$ O, and $^{40}$ Ca. Theoretical uncertainties originating from the neural network interpolation and the Hamiltonian dependence are assessed. We also present a calculation of charged-current responses of $^{16}$ O and the flux-averaged total $ν_{μ} -^{12}$ C cross section. Our model shows good agreement with experimental data within the range of validity of our approximations. The framework can be readily extended to include additional dynamical mechanisms, such as pion production, as well as other nuclear Hamiltonians.
Comments:
14 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
arXiv:
2608.23057 [pdf]
0 citations
09
[Submitted on 24 Aug 2026]
Open Quantum Systems Approaches for Heavy-Ion Collisions
Alexander Rothkopf
In this contribution to Strangeness in Quark Matter 2026, I review the open quantum systems approach, a modern theoretical framework for addressing the interaction of a quantum system with its environment, and highlight recent progress in its application to the understanding of in-medium heavy quarkonium in relativistic heavy-ion collisions.
Comments:
9 pages, 5 figures; invited plenary talk at the Strangeness in Quark Matter 2026 conference, March 27th 2026, UCLA, Los Angeles, USA
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2608.23147 [pdf]
0 citations
10
[Submitted on 20 Aug 2026] (cross-list from hep-ph)
A Hydrogen-Like Model for Pion and Kaon Masses Based on Dirac Quark-Hamiltonians and Numerical Methods
Zhenhua Ning🇺🇸 · A. S. Davuluru🇺🇸 · H. Raposo🇺🇸 · Jong-Ping Hsu🇺🇸
We consider a relativistic hydrogen-like model for meson mass spectra. The model is based on a Lagrangian with a new general Yang-Mills symmetry. The strong interactions involve a fourth-order field equation that generates a linear confining potential. Notably, this model for meson masses requires quarks to carry only a single `confining charge' $f_{c}$ rather than three color charges. We classify meson mass spectra into sub-spectra defined by isospin, G-parity, total angular momentum and parity. By applying a numerical solver to the Dirac Hamiltonians--incorporating two short-range confining potentials, we obtain energy eigenvalues in natural units. The model has three coupling constants and one parameter. It provides a robust fit of 31 pions and kaons masses (from $\approx 140 M e V$ to $\approx 2, 300 M e V$ ) to within $\approx 18%$ of relative percentage error. The model suggests that the confining charge $f_{c}$ =0.045/MeV = 8.87 fm plays the role of the basic length in the quark interactions.
Comments:
11 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2608.21459 [pdf]
0 citations
11
[Submitted on 21 Aug 2026] (cross-list from hep-ph)
Photon production from gluon splitting and fusion induced by a magnetic field of arbitrary strength in relativistic heavy-ion collisions
Alejandro Ayala🇲🇽 · Santiago Bernal-Langarica🇲🇽 · José Jorge Medina-Serna🇲🇽 · Ana Julia Mizher🇧🇷
We compute the yield and elliptic flow coefficient for photons produced during the pre-equilibrium stage of semi-central relativistic heavy-ion collisions from the gluon fusion and splitting processes induced by the presence of a magnetic field. The calculation is performed for arbitrary values of the field strength. The pre-equilibrium gluon distribution is modeled with a glasma-inspired Bose-Einstein occupation factor, as well as with an anisotropic distribution that accounts for the rapid initial expansion along the beam axis. In both cases, we find a very good agreement between the calculation and the experimental data from PHENIX. Most notably, the shape and strength of the elliptic flow coefficient are described quite well, representing a step towards solving the outstanding photon puzzle.
Comments:
17 pages, 10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2608.21600 [pdf]
0 citations
12
[Submitted on 22 Aug 2026] (cross-list from hep-ph)
Phase-constrained $Σ^{*}$ spectroscopy in the pure- $I = 1$ reactions $K_{L} p \to π^{+} Σ^{0}$ and $K_{L} p \to π^{+} Λ$
Dan Guo🇨🇳 · Marshall B. C. Scott🇺🇸 · Igor Strakovsky🇺🇸 · Fu-Rong Xu🇨🇳 · Bing-Song Zou🇨🇳
Low-energy $K ˉ N$ scattering provides direct access to strange-baryon spectroscopy, but conventional charged-kaon reactions mix the $I = 0$ and $I = 1$ amplitudes. Motivated by the isospin-selective nature of the $K_{L} p$ reactions, we present, to our knowledge, the first simultaneous analysis of the pure- $I = 1$ reactions $K_{L} p \to π^{+} Σ^{0}$ and $K_{L} p \to π^{+} Λ$ in which a common set of resonance parameters and a fixed relative-phase convention are imposed on both final states. Within an effective-Lagrangian model, a joint fit of available differential cross sections and recoil polarizations yields $χ^{2} / d.o.f. = 1.604$ . We find clear channel complementarity: the $t$ -channel $K^{*}$ exchange is more important in $K_{L} p \to π^{+} Λ$ , especially at forward angles, whereas $K_{L} p \to π^{+} Σ^{0}$ is more sensitive to the contribution of $Σ (1620) 1/ 2^{-}$ . At the same time, $Σ (1660) 1/ 2^{+}$ remains important through interference effects in both channels. These results demonstrate the importance of multichannel, phase-constrained analyses for establishing the $I = 1$ hyperon spectrum and provide timely phenomenological input for future high-precision measurements by the KLF program at JLab. Once the pure $I = 1$ amplitudes are reliably determined, they will also enable the separation of the $I = 0$ component in the much more abundant $K^{-} p \to π^{\pm} Σ^{\mp}$ data, opening a path toward a more quantitative study of the $Λ^{*}$ spectrum.
Comments:
6+8 pages, 3+4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2608.21824 [pdf]
0 citations
13
[Submitted on 23 Aug 2026] (cross-list from hep-ph)
Long-range scalar interactions in the effective field theory approach to $0 ν β β$
Fahim Ahmed🇺🇸
As a lepton-number-violating process whose observation would establish the Majorana nature of neutrinos, neutrinoless double-beta decay ( $0 ν β β$ ) is an important low-energy nuclear probe of beyond-the-Standard-Model physics. Effective field theory (EFT) provides a general, model-independent description, and interference among effective mechanisms is essential for disentangling their contributions to the total decay rate. We focus on scalar-type terms of the long-range Lagrangian in the EFT approach to $0 ν β β$ . We simultaneously retain the two scalar interactions involving a common $(S + P)$ leptonic current coupled either to an $(S - P)$ or an $(S + P)$ hadronic current. Their coherent contribution produces mutual interference between the two scalar mechanisms, controlled by the relative complex phase of their couplings, in addition to their separate interference with the standard mass mechanism. We give a compact half-life expression, the explicit scalar--scalar interference coefficient in terms of scalar nuclear-matrix-element ratios and integrated phase-space factors, and a positivity bound on that coefficient. The calculation uses the closure and single-nucleon impulse approximations, retains the dominant scalar recoil subset, and includes the $s_{1/2}$ and $p_{1/2}$ Coulomb waves of the outgoing electrons. The resulting dimensionally explicit formulation provides a basis for correlated analyses of the two scalar coefficients.
Comments:
29 pages, 1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2608.22369 [pdf]
0 citations
14
[Submitted on 23 Aug 2026] (cross-list from hep-ph)
Eikonal Expansion for Classical Gluon Fields: from Weak to Strong
Shane Brown🇺🇸 · Alex DeBrizzi🇺🇸 · Alex Kovner🇺🇸
We develop a formal procedure of eikonal expansion for classical fields in gluodynamics. We show that in the weak field limit the expansion is straightforward and determines the eikonal components of vector potentials in terms of eikonal components of color currents via classical equations motion. We demonstrate that the recently proposed Born-Oppenheimer high energy evolution yields the ground state wave function interpretable in terms of the classical fields. The relevant classical field is indeed consistent with the eikonal expansion, and contains the leading eikonal and subeikonal components. For strong fields we find that the naive eikonal expansion is inconsistent, as nonlilearities in equations of motion lead to mixing of eikonal orders. Thus the effect of subeikonal components on the leading eikonal component is not suppressed by the eikonality parameter. We show that this problem can be rectified by classically "integrating out" high longitudional momentum components of gluon fields. This leads to a classical action for the low momentum components with small self interaction, but strongly renorlamized currents, which contain contribution due to high momentum modes.
Comments:
41 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2608.22536 [pdf]
0 citations
15
[Submitted on 23 Aug 2026] (cross-list from hep-ph)
Charmonia at Finite Momentum and Spatial Correlators in Quark-Gluon Plasma
Thomas Hardin🇺🇸 · Ralf Rapp🇺🇸
Spatial correlation functions of quarkonia in the quark-gluon plasma are available from finite- temperature lattice-QCD with good precision. However, their interpretation in terms of microscopic spectral functions has been challenging due to a highly oscillating momentum integral in their Fourier transform and the need for a reliable evaluation of their 3-momentum dependence. Utilizing the thermodynamic T-matrix approach we first obtain a Lorentz-covariant scattering equation by taking advantage of a separable-potential approximation. Medium effects are included through state-of-the- art heavy-quark selfenergies and a potential screening which we constrain by euclidean correlators from lattice QCD. In addition to the usual two-particle cut in the scattering equation we also include particle-hole excitations, also referred to as zero mode. We find that both the increase of euclidean correlators with 3-momentum and the suppression of the spatial correlators found in lattice-QCD can be qualitatively reproduced, with the zero mode playing an essential role for the former but not for the latter.
Comments:
8 pages and 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2608.22596 [pdf]
0 citations
16
[Submitted on 24 Aug 2026] (cross-list from hep-ph)
Revisiting the $Λ (1405)$ pole structure with convolutional neural networks
Julius B. Pagayon · Vince Angelo A. Chavez · Denny Lane B. Sombillo
We revisit the long-standing ambiguity surrounding the complex pole structure of the $Λ (1405)$ resonance by reframing it as a classification problem for convolutional neural networks (CNNs). By training our models to recognize subtle geometric variations on nearly degenerate lineshapes using targeted differential feature on empirical CLAS data, we establish a data-driven consensus on large inference samples. Our results show that the analytic structure characterized by two poles on the $[b t]$ sheet and additional pole on the $[bb]$ sheet globally dominates. The inference-guided pole parameter extraction reveals that the $Λ (1405)$ is a two-state system, characterized by a molecular state sitting below the $K ˉ N$ threshold and a non-molecular state lying above the $Σ π$ threshold.
Comments:
14 pages, 5 figures, comments are welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2608.22747 [pdf]
0 citations
17
[Submitted on 24 Aug 2026] (cross-list from hep-ph)
$Δ$ resonance contributions to QED radiative corrections in neutron and inverse beta decay
Oleksandr Tomalak🇨🇳 · Yi-Bo Yang🇨🇳
We incorporate the $Δ (1232)$ resonance into pion-induced QED radiative corrections to neutron decay and inverse beta decay (IBD). Within the framework of heavy-baryon chiral perturbation theory with explicit $Δ$ degrees of freedom, we compute additional contributions and study their impact on IBD cross sections and on the renormalization of the nucleon isovector vector and axial-vector charges. $Δ$ resonance does not renormalize the vector charge. For the axial-vector charge, including the $Δ$ resonance restores power counting and significantly reduces the QED radiative correction to the experiment-over-lattice-QCD ratio $g_{A} / (g_{A}^{QCD} g_{V})$ , bringing it to zero within radiative-correction uncertainties. $Δ$ resonance increases the pion-induced QED radiative corrections to IBD by a factor $1.2$ - $1.3$ .
Comments:
19 pages, 1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2608.22845 [pdf]
0 citations
18
[Submitted on 24 Aug 2026] (cross-list from astro-ph.HE)
Neutron star masses from electron-capture supernovae under equation-of-state uncertainties
Vishal Parmar · Domenico Scordino · Ignazio Bombaci
Electron-capture supernovae (ECSNe) are a promising formation channel for low-mass neutron stars, but the minimum gravitational mass of the neutron stars they produce depends on both the progenitor core structure and the neutron-star matter equation of state (EOS). We compute the electron-capture (EC) threshold gravitational mass ( $M_{W D}^{⋆}$ ) of cold white-dwarf-like O--Ne--Mg cores with representative compositions and map the baryon number onto cold neutron-star configurations constructed from a Bayesian ensemble of unified crust--core EOSs. Although the EC threshold density is sensitive to the concentrations of the O--Ne--Mg mixture, the threshold baryon number of the O--Ne--Mg core varies only weakly, producing a narrow remnant-mass window. In the baseline case with no baryonic mass loss during the transition from the EC threshold mass O--Ne--Mg core to the remnant neutron star, standard ECSNe yield remnant neutron stars with gravitational masses of $1.24$ -- $1.265 M_{⊙}$ , with only a small EOS-induced spread. Small baryonic mass losses of $0.01$ -- $0.02 M_{⊙}$ shift this range modestly downward, but the $1.174 M_{⊙}$ companion of PSR J0453+1559 would require an extreme mass loss close to $0.10 M_{⊙}$ , which is not favored by current ECSN simulations. We find that the residual EOS dependence of the remnant mass is controlled mainly by the pressure around nuclear saturation density, while the corresponding tidal deformability remains sensitive to the remnant radius and compactness. Thus, low-mass double neutron star systems can in principle connect ECSN-like formation channels with gravitational-wave constraints on the EOS. Our results show that ECSNe naturally form low-mass neutron stars, but within a restricted mass range; the lightest observed neutron stars likely require low-mass iron-core collapse, ultra-stripped supernovae, or other nonstandard channels.
Comments:
12 pages, 6 figures. To appear in A&A
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2608.23122 [pdf]
0 citations
19
[Submitted on 24 Aug 2026] (cross-list from hep-ph)
Radiative decays of the isoscalar $S$ -wave $D D ˉ$ molecule
Yuan-Jun Gao🇨🇳 · Gang Li🇨🇳 · Shi-Dong Liu🇨🇳 · Pan-Pan Shi🇪🇸
In the hadronic molecular picture, an isoscalar $S$ -wave $D D ˉ$ molecule is naturally expected as the spin-0 partner of $X (3872)$ . Assuming this state, denoted by $X_{0}$ , to be a pure $D D ˉ$ molecule with quantum numbers $J^{P C} = 0^{++}$ , we investigate its radiative decays $X_{0} \to γ V (V = ρ^{0}, ω)$ within an effective Lagrangian framework. The decay amplitudes are generated by intermediate charmed-meson loops, with electromagnetic gauge invariance consistently maintained throughout the calculation. We evaluate the partial decay widths and examine their dependence on the $X_{0}$ mass and the cutoff. Although the individual decay widths exhibit a sizable dependence on the cutoff, their ratio is remarkably stable. In particular, we obtain that the ratio for the decays $X_{0} \to γ ρ^{0}$ and $X_{0} \to γ ω$ is approximately 2.26, which is insensitive to the variation of the cutoff. This robust ratio provides a useful model-insensitive signature of the molecular structure of $X_{0}$ .
Comments:
9 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2608.23332 [pdf]
0 citations
20
[Submitted on 24 Aug 2026] (cross-list from hep-th)
Landau theory, effective temperature, and tricritical phenomena in a holographic nonequilibrium steady state
Motohiro Kanazawa🇯🇵 · Masataka Matsumoto🇯🇵 · Shin Nakamura🇯🇵
We investigate the critical exponents $(γ, ν)$ at the current-driven tricritical point (TCP) associated with chiral symmetry breaking in a nonequilibrium steady state described by the D3/D7 model. In the symmetry-broken phase, we find that, unlike in the conventional Landau theory, both $γ$ and $ν$ can take values different from those predicted by the Landau theory and depend on the path along which the TCP is approached in the phase diagram. However, when the TCP is approached with the ratio of the effective temperature to the heat bath temperature, $T_{*} / T$ , held fixed, the critical exponents agree with those of the Landau theory. These results suggest that the critical phenomena at the current-driven TCP may be described by the Landau theory along the $T_{*} / T$ -fixed line, whereas a nontrivial extension of the Landau theory is required for a more general description of the critical phenomena along arbitrary paths.
Comments:
20 pages, 9 figures
Subjects:
High Energy Physics — Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)
arXiv:
2608.23378 [pdf]
0 citations
21
[Submitted on 24 Aug 2026] (cross-list from hep-ph)
Imprints of nuclear shell structure in exclusive vector meson production
Arpita Mondal🇮🇳 · Arjun Kumar🇺🇸 · Debojit Sarkar🇮🇳
We report for the first time that, within the saturation framework, exclusive vector meson production at small $x$ is sensitive to the shell structure of the target nucleus. Self-consistent nuclear densities from occupied single-particle orbitals in the quark-meson coupling (QMC) model modify the coherent $∣ t ∣$ -differential cross section, enhancing the secondary diffractive lobes for light nuclei and displacing the higher-order minima in $∣ t ∣$ for intermediate-mass nuclei, whereas for heavy targets the shifts are weaker and appear at larger $∣ t ∣$ . Because the small $J / ψ$ dipole is insensitive to saturation, these features make coherent $J / ψ$ production a clean probe of nuclear shell structure, most favorably for intermediate-mass nuclei such as the calcium isotopes. For the larger $ϕ$ dipole, shell structure must be included in the nuclear initial state before saturation effects can be isolated in differential observables at the EIC. Our results establish exclusive vector meson production as a probe of the mean-field, single-particle structure of nuclei at small $x$ , and provide a baseline for isolating residual many-body correlations.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2608.23445 [pdf]
0 citations
22
[Submitted on 24 Aug 2026] (cross-list from nucl-ex)
Core Breaking at Low Spin in $^{68}$ Zn from Nuclear Resonance Fluorescence
S. R. Johnson · R. V. F. Janssens · B. A. Brown · A. D. Ayangeakaa · S. S. Bhattacharjee · E. Churchman · S. W. Finch · U. Friman-Gayer · S. Frye · M. Fulghieri · D. Gribble · X. H. -K. James · R. Longland · C. Wegner
Low-spin excited states in $^{68}$ Zn have been studied at the High Intensity Gamma-Ray Source (HI $γ$ S) from the ground state up to the particle emission threshold using the nuclear resonance fluorescence technique (NRF) and the newly developed Clover Array. Low-spin levels were excited by linearly-polarized, $2.90 - 9.79$ MeV photon beams. Spin-parity quantum numbers as well as associated $M 1$ and $E 1$ decay strengths were determined for a large fraction of the 158 states observed. In addition, long-duration coincidence measurements at 9.46 and 9.79 MeV enabled the investigation of the level scheme near the ground state. The results have been interpreted with shell-model calculations using two different model spaces and several effective interactions often used to describe nuclei in this mass region. While the structure near the ground state can be understood in terms of excitations involving solely valence nucleons, core breaking is required to account for the evolution of the total $M 1$ strength at excitation energies above $\sim 5$ MeV.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2608.23514 [pdf]
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first authorsco-authorsvia INSPIRE