Nuclear Theory·nucl-th

Wednesday·March 11, 2026

17 papers—3 primary·14 cross-listed

01
Effects of shape coexistence and configuration mixing on low-lying states in tellurium isotopes
Kosuke Nomura
Low-energy quadrupole collective states in even-even tellurium (Te) isotopes are studied using the interacting boson model with configuration mixing. The corresponding Hamiltonian is determined by means of the microscopic nuclear structure calculations within the self-consistent mean-field method employing a given energy density functional and pairing interaction. Calculated low-energy levels for nonyrast states show a parabolic behavior characteristic of the shape-coexisting structure. The intruder prolate-shape configuration is shown to mix strongly with the normal oblate-shape configuration, and play an important role in determining the low-lying structure in the Te isotopes near the middle of the neutron major shell closures.
nucl-thnucl-exPRC(2026)·1 citation
02
Microscopic Investigation of Fusion and Quasifission Dynamics
Liang Li · Xiang-Xiang Sun · Lu Guo
We introduce the application of Time-Dependent Hartree-Fock (TDHF) theory to two key aspects of heavy-ion reaction dynamics for producing superheavy elements: fusion and quasi-fission (QF). For fusion reactions $^{48}$ Ca+ $^{238}$ U, the capture cross sections, fusion probabilities, and evaporation-residue cross sections are calculated using the inputs from TDHF simulations, and the results are found to be in reasonable agreement with available experimental data. For the QF process of $^{48}$ Ca+ $^{249}$ Bk, we show the distribution of the fragments and investigate the impact of the tensor force, significantly enhancing the role of spherical shell effects.
nucl-thEPJ Web Conf.(2026)·0 citations
03
Physics-structured cooperative neural network for baseline-free nuclear mass modeling
Peiwen Zai · Wei Cheng · Feng-Shou Zhang
Machine learning approaches can improve nuclear mass modelling, but the most accurate strategies often depend on a theoretical mass baseline or hand-crafted physics features. We test whether a modular architecture encoding selected nuclear-structure priors improves baseline-free direct prediction and yields informative branch diagnostics. The Cooperative Neural Network (CoNN) implements this approach through four form-constrained branches: a smooth macroscopic network, discrete embeddings, a two-dimensional regional grid, and a parity-aware network. It extracts complementary patterns from (Z, N) through these branches and sums their outputs to predict binding energies without a theoretical mass-model baseline. Thus, the model retains physics priors while reducing its reliance on engineered input features. On AME2020, CoNN reaches a root-mean-square deviation (RMSD) of 0.269 MeV for 3558 nuclei, compared with 0.836 MeV for a parameter-matched unstructured MLP. It also gives RMSDs of 0.419 MeV on a held-out interpolation subset and 0.728 MeV on 122 nuclei newly measured since AME2016. The learned branch outputs show recognizable physical patterns, including embedding shell-kink signatures at major magic numbers and odd-even staggering along isotopic chains. These results identify architecture-level priors as a practical route to baseline-free mass prediction, with learned components that help diagnose both nuclear-structure patterns and extrapolation limits.
nucl-th1 citation
04
Sensitivity of Jet Observables to Molière Scattering Off Quasiparticles in Quark-Gluon Plasma
Zachary Hulcher🇺🇸 · Arjun Srinivasan Kudinoor🇺🇸 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸
Quark-gluon plasma (QGP) is a strongly coupled liquid when viewed at length scales of order the inverse of its temperature and longer. However, when it is probed at short enough length scales, asymptotic freedom mandates the presence of quark- and gluon-like quasiparticles. Partons in jets can trigger perturbative, high momentum-exchange $2 \to 2$ Molière scatterings off quasiparticles in the medium, making jets useful probes of the microscopic structure of QGP. Prior to this work, soft strongly coupled momentum-exchanges between jet partons and the QGP droplet produced in a heavy-ion collision, as well as the wakes that jets excite in the droplet, had been accounted for in the Hybrid Model of jet quenching. Here, we present a full calculation of Molière scattering off a QGP quasiparticle which results in the deflection of the jet parton and the excitation of a parton from the thermal medium that recoils after being kicked, and describe how it is implemented in the Hybrid Model. The scattered jet and recoil partons continue to propagate through the QGP, lose energy and momentum, excite wakes, and may further re-scatter. Using the Hybrid Model, we study how Molière scatterings impact jet shapes and fragmentation functions, the Soft Drop angle $R_{g}$ , jet girth $g$ , and observables that focus on the number and angular distribution of subjets within jets. We demonstrate that photon-tagged jets provide a particularly sensitive probe: selecting events by the photon energy mitigates the selection bias inherent in inclusive jet measurements and enhances sensitivity to rare large-angle scatterings. We find that Molière scatterings broaden both the $R_{g}$ and $g$ distributions when jets significantly softer than the photon are included. Our results point the way towards distinctive model-independent experimental signatures of hard scattering of jet partons off quasiparticles in QGP.
↳ hep-phhep-thnucl-exnucl-th4 citations
05
Gamma-ray Signatures of r-Process Radioactivity from the Collapse of Magnetized White Dwarfs
Tetyana Pitik · Yong-Zhong Qian · David Radice · Daniel Kasen
We predict the gamma-ray line emission from $r$ -process nuclei synthesized in the ejecta of the accretion-induced collapse (AIC) of a magnetized, rapidly rotating white dwarf. Using ejecta from a two-dimensional general-relativistic neutrino-magnetohydrodynamic simulation, further evolved with a radiation-hydrodynamics code coupled to an in-situ nuclear reaction network, we construct angle-dependent gamma-ray spectra in the $0.01$ - $10 MeV$ band via composition-dependent ray-tracing through the ejecta. The emission between $\sim$ 1 and $10$ d is dominated by $^{132}$ I ( $t_{1/2} = 2.3$ h), continuously replenished by the decay of its parent $^{132}$ Te ( $t_{1/2} = 3.2$ d), with additional contributions from $^{131}$ I, $^{133}$ Xe, and $^{132}$ Te. At $t ≳ 20$ d, $^{56}$ Co (from $^{56}$ Ni decay) becomes the primary emitter. The simultaneous presence of $r$ -process and iron-peak gamma-ray lines is distinctive of AIC ejecta and absent in binary neutron star mergers, where iron-peak nuclei are generally not synthesized. Comparing with the $3 σ$ continuum sensitivities of planned MeV gamma-ray telescopes (COSI, AMEGO-X, e-ASTROGAM, GRAMS, GammaTPC), we find the brightest $r$ -process lines detectable to $\sim 10 Mpc$ by GammaTPC and GRAMS, with the signal approaching their sensitivity threshold at $30 Mpc$ . The $r$ -process spectral features survive time integration over $\sim 30$ d exposures, demonstrating robustness against the long observation times required by gamma-ray detectors.
↳ astro-ph.HEnucl-thPRD(2026)·2 citations
06
DIS dijet production in Background Field Approach: General formalism and methods
Tiyasa Kar🇺🇸 · Andrey Tarasov🇺🇸 · Vladimir V. Skokov🇺🇸
We develop a general formalism for computing physical observables within the background field approach, based on representing propagators of the Feynman diagrams in the background fields as path-ordered exponents. This representation allows systematic expansion of the background fields onto arbitrary linear piecewise contours in coordinate space, yielding gauge-covariant QCD operators to any required order of the expansion. We apply this formalism to DIS dijet production and derive a general form of the cross section in terms of (anti)quark propagators in the background fields, valid in arbitrary kinematics. To demonstrate the versatility of our approach, we consider two kinematic limits. In the back-to-back limit, the expansion contour reduces to that of TMD operators. In this limit we recover the known leading-power results. In the small- $x$ regime, defined by the high-energy power counting for boosted background fields, the expansion contour assumes a staple-like shape. We find that, at the leading eikonal order, the transverse component of the background field $B_{i}$ , though parametrically suppressed relative to the light-cone component, contributes non-trivially through the field-strength tensor $F_{- i}$ and the transverse gauge links. Setting $B_{i} = 0$ recovers the standard CGC result. We also demonstrate matching between the eikonal and back-to-back expansions, providing a quantitative dictionary between these two distinct kinematic regimes.
↳ hep-phnucl-thPRD(2026)·3 citations
07
Mass measurements of $^{179 - 184}$ Yb identify an anomalous proton-neutron interaction
C. L. Brown🇬🇧 · J. Ash🇨🇦 · B. Ashrafkhani🇨🇦 · J. Bergmann🇩🇪 · T. Brunner🇨🇦 · J. D. Cardona🇨🇦 · R. B. Cakirli🇩🇪 · R. F. Casten🇺🇸 · C. Chambers🇨🇦 · T. Dickel🇩🇪 · G. Gwinner🇨🇦 · Z. Hockenbery🇨🇦 and 21 other authors
Mass measurements of nuclei can identify structurally-driven trends in binding energy across isotopic chains, and can also isolate specific nucleon-nucleon interactions, such as the $δ V_{pn}$ interaction of the last two valence protons with the last two valence neutrons. Below $^{208}$ Pb, investigation of the local binding energy and $δ V_{pn}$ systematics can facilitate a better understanding of the behaviour of the proton-neutron interaction in the 'hole-hole' regime (where valence interactions can be modelled in hole-space rather than particle-space) and provide insight on the potential onset of a prolate-to-oblate shape transition. However, measurement of the necessary nuclei has been exceptionally challenging. Here we present six first-time measurements of neutron-rich ytterbium, using advanced rare isotope production and mass spectrometry techniques, leading to the identification of an anomalously strong proton-neutron interaction in the 'hole-hole' quadrant below $^{208}$ Pb. The scale of this interaction, at $^{186}$ Hf, is comparable to that of similar signals at doubly-magic nuclei and shape transitions. The experimental results are compared with contemporary mean-field model predictions, that do not accurately reproduce the anomaly. The results are also used to benchmark predictions from several models, to facilitate more accurate descriptions towards a key r-process waiting point at $N = 126$ .
↳ nucl-exnucl-th1 citation
08
Extracting freeze-out conditions in beam energy scan via functional QCD
Yi Lu🇨🇳 · Christian S. Fischer🇩🇪 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳 · Jan M. Pawlowski🇩🇪
Fluctuations of conserved charges provide a link between high quality theoretical results and precision measurements of heavy ion collisions. We compare results for ratios of the lowest order baryon number susceptibilities from functional QCD approaches to proton number cumulants extracted from experiments. We find that they meet at a specific temperature and chemical potential for each collision energy. This is indicative of the respective freeze-out point. From this self-consistent determination of the freeze-out parameters we extract a prediction for the kurtosis on the freeze-out line. We find quantitative agreement with experimental data where available, despite comparing apples (baryons) with oranges (protons). At a collision energy around 5 GeV, our kurtosis exhibits a peak structure indicative of the critical end point of QCD.
↳ hep-phhep-exnucl-th8 citations
09
High-Order Matrix Numerov for Singular Potentials
Nir Barnea
The matrix Numerov method provides an efficient framework for solving the time-independent Schrödinger equation as a matrix eigenvalue problem. However, for singular potentials such as the Coulomb interaction, the expected fourth-order convergence deteriorates for low angular momenta due to the behavior of the potential near the origin. We show that this loss of accuracy originates from an implicit boundary assumption in the standard formulation. By incorporating analytic near-origin information into the discretized Hamiltonian, we derive simple boundary corrections that restore fourth-order convergence and can even produce higher convergence rates for $s$ - and $p$ -wave energies. The resulting scheme preserves the simplicity and computational efficiency of the original method while significantly improving its accuracy for singular potentials.
↳ physics.atom-phnucl-th2 citations
10
Joint Bayesian analysis of soft and high- $p_{⊥}$ probes yields tighter constraints on QGP properties
Marko Djordjevic🇷🇸 · Dusan Zigic🇷🇸 · Igor Salom🇷🇸 · Magdalena Djordjevic🇷🇸
To extract bulk QGP properties, we perform a joint Bayesian calibration of bulk-medium parameters using low- $\pt$ bulk and high- $\pt$ tomography within a common medium evolution. Low- $\pt$ observables are computed with \textsc{TRENTo}+\textsc{VISHNU}; temperature profiles are passed to \textsc{DREENA-A} to predict light/heavy $R_{AA} (\pt)$ and $v_{2} (\pt)$ . Gaussian-process emulation enables Hamiltonian Monte Carlo sampling of the low- $\pt$ -only and joint posteriors. The low- $\pt$ -only case underpredicts high- $\pt$ anisotropy; the joint calibration matches both sectors and markedly tightens bulk-parameter constraints, demonstrating the added power of high- $\pt$ data.
↳ hep-phnucl-th0 citations
11
JLab and J-PARC for the J/{\ensuremath{\psi}} Production at the Threshold
Igor I. Strakovsky (GWU)🇺🇸 · Jung Keun Ahn (Korea U.)🇺🇸 · William J. Briscoe (GWU)🇰🇷 · Misha G. Ryskin (PNPI)🇷🇺 · Axel Schmidt (GWU)🇺🇸
New threshold measurements for $γ p \to p J / ψ \to p (μ^{+} μ^{-})$ by 007 and $γ^{*} p \to p J / ψ \to p (e^{+} e^{-})$ by CLAS12 allow us to extend the previous phenomenological determination of the J/\ensuremath{\psi}-proton scattering length, $α_{J / ψ p}$ , using GlueX threshold data for $γ p \to p J / ψ \to p (e^{+} e^{-})$ . The agreement between all three J/\ensuremath{\psi} data sets shows no indication of systematic differences between methodologies. Furthermore, perturbative QCD predictions support the phenomenological determination of heavy vector meson-nucleon scattering lengths. The role of the nucleon form factor, $F_{N}$ , is discussed, and a possible correction to the phenomenological scattering length for heavy vector meson photoproduction is calculated using the pole form of $F_{N}$ . Upcoming J-PARC threshold measurements of the reaction $π^{-} p \to n J / ψ \to n (l^{+} l^{-})$ will help to evaluate the possible role of heavy pentaquark, $P_{c}$ , states in low-energy $J / ψ$ production and the effects caused by the nucleon form factors.
↳ hep-phhep-exnucl-exnucl-thPRD(2026)·1 citation
12
The eikonal spin-dependent Odderon and gluon Sivers function of a proton, and its small- $x$ evolution
Sanjin Benić🇭🇷 · Adrian Dumitru🇺🇸 · Florian Hechenberger🇺🇸 · Tomasz Stebel🇵🇱
The matrix element in the proton of the eikonal Odderon operator, with a helicity flip, has been shown to correspond to the dipole gluon Sivers function. We employ a three quark light-front model of the proton to determine the Sivers function at moderately small $x_{0} \sim 0.1$ and transverse momentum $k_{⊥} ≲ 1$ ~GeV. The model light-cone (LC) wave function predicts the properties of $x f_{1 T}^{⊥ g} (x, k_{⊥})$ such as its overall magnitude, the position of its peak in $k_{⊥}$ , and its behavior at small $k_{⊥}$ . We then compute numerically the BFKL anomalous dimension characterizing the power-law tail at $k_{⊥} ≳ 1.5$ ~GeV of the gluon Sivers function at small (but pre-asymptotic) LC momentum fractions, $α_{s} lo g x_{0} / x = 1$ : $x f_{1 T}^{⊥ g} (x, k_{⊥}) \sim k_{⊥}^{- 3.3}$ .
↳ hep-phnucl-thPRD(2026)·2 citations
13
Extracting the speed of sound of QCD from transverse momentum fluctuations
Mubarak Alqahtani🇸🇦 · Tribhuban Parida🇵🇱 · Jean-Yves Ollitrault🇫🇷
We extract the speed of sound ( $c_{s}$ ) in the quark-gluon plasma from ATLAS data on the probability distribution of the transverse momentum per particle, $[p_{T}]$ , in ultra-central Pb+Pb collisions. With an ideal detector, $c_{s}$ can be inferred from the rise of the mean $[p_{T}]$ with the collision multiplicity. In practice, however, low- $p_{T}$ particles escape detection, which biases the analysis. We show how to correct for this bias by using data on the variance of $[p_{T}]$ , as well as information from the recently-measured $v_{0} (p_{T})$ . We also introduce a systematic method for deblurring the noise from the hadronization process. Assuming that the size of the quark-gluon plasma is independent of the hadron multiplicity in collisions at zero impact parameter, which is the scenario preferred both by high-energy QCD and heavy-ion data, we obtain $c_{s} / c = 0.496 \pm 0.008$ at temperature $T = 221 \pm 13$ ~MeV, in perfect agreement with first-principles calculations from lattice QCD.
↳ hep-phhep-exnucl-exnucl-thPLB(2026)·1 citation
14
Event-by-Event Multiplicity Cumulants as Probes of Partonic Energy Loss and Phase Structure in Au+Au Collisions within a Modified HIJING Model
Y.A. Rusak🇧🇾 · L.F. Babichev🇧🇾
Event-by-event fluctuations of charged hadron multiplicity, net-baryon, and net-electric charge are investigated in central Au+Au collisions at $s_{N N} =$ 20-200 GeV using a modified HIJING Monte Carlo generator. The model incorporates QCD-based partonic energy loss formalisms in both hot (quark-gluon plasma) and cold media, eliminating free tuning parameters. At energies above 100 GeV/nucleon, multiplicity and net-charge fluctuations serve as sensitive probes for medium properties, showing strong agreement with STAR data when hot-medium finite-size effects are included. By introducing a probabilistic distribution for a first-order phase transition, we demonstrate that multiplicity cumulant ratios ( $σ^{2} / M$ and $S σ$ ) provide distinctive signatures of a binodal transition, whereas net-charge and net-baryon fluctuations remain relatively insensitive. Furthermore, expanding the kinematic acceptance significantly enhances the sensitivity of these multiplicity fluctuations to the phase transition boundary.
↳ hep-phnucl-th0 citations
15
Overview of recent UPC measurements
Anisa Khatun (on behalf of the ALICE Collaboration)🇮🇹
This contribution presents an overview of recent measurements of photon-induced processes in ultra-peripheral collisions (UPCs) performed with the ALICE experiment at the LHC. Results from Run~2 include detailed studies of exclusive vector meson photoproduction in Pb-Pb collisions. Measurements of incoherent J/ $ψ$ photoproduction as a function of energy and the Mandelstam- $∣ t ∣$ variable, combined with electromagnetic dissociation (EMD) classification, show a suppression of the energy evolution at large $∣ t ∣$ , favouring saturation-based descriptions of the gluon structure. Complementary measurements of proton emission in Pb-Pb UPCs constrain nuclear breakup mechanisms and provide a handle on collision geometry through EMD tagging. Coherent $ρ^{0}$ photoproduction exhibits impact-parameter-dependent azimuthal anisotropy consistent with quantum interference effects, while the first polarisation measurement of coherently photoproduced J/ $ψ$ confirms $s$ -channel helicity conservation. Additional measurements of exclusive multi-hadron photoproduction, including four-pion and charged kaon pair final states, probe resonance contributions and light vector meson couplings to photons and nuclear targets. Run~3 data enable the study of inclusive photonuclear interactions. Measurements of inclusive open charm photoproduction constrain the gluon content of nuclei in the perturbative QCD regime. Studies of identified hadron production and baryon-to-meson ratios in photonuclear collisions provide new information on particle production mechanisms and possible collective effects in photon-induced systems. Photon-photon interactions are also studied through performance and sensitivity analyses for the measurement of the anomalous magnetic moment of the tau lepton, together with projections for future measurements with ALICE~3.
↳ nucl-exnucl-thPoS(2026)·0 citations
16
Jet energy loss in anisotropic plasmas meets limiting attractors
Kirill Boguslavski🇫🇷 · Lucas Hörl🇦🇹 · Florian Lindenbauer🇦🇹
We consider the energy loss of a high-energy parton in the early anisotropic plasma in heavy-ion collisions. Working in the harmonic approximation, we compute the change in the mean energy of an emitted gluon in the presence of an anisotropic background, characterized by anisotropic jet quenching parameters $q^_{x} \neq = q^_{y}$ . Evaluating the resulting integrals numerically, we compare with isotropic media, and obtain a simple pocket formula to estimate the impact of anisotropy on the mean emitted gluon energy, which is generally small. We then combine our results with the values of the jet quenching parameter extracted from QCD kinetic theory simulations and show that the medium length dependence of this mean energy loss exhibits the characteristics of limiting attractors, which can be obtained by extrapolating to zero and infinite coupling. Our study thus relates energy loss of jet partons to universal dynamics of anisotropic plasmas.
↳ hep-phhep-exnucl-th0 citations
17
Does hot QCD have a conformal manifold in the chiral limit?
Shi Chen🇺🇸 · Aleksey Cherman🇺🇸 · Robert D. Pisarski🇺🇸
Recent lattice evidence suggests the chiral phase transition in QCD is second-order for $N_{f} \geq 2$ massless flavors. We constrain CFT descriptions of a critical line in temperature $T$ and imaginary baryon chemical potential $θ_{B} = i μ_{B} / T$ . An 't Hooft anomaly at general $θ_{B}$ constrains the transition even at $θ_{B} = 0$ , leaving only three minimal scenarios. The best-motivated scenario for $N_{f} \geq 3$ , and perhaps also $N_{f} = 2$ , is beyond Ginzburg-Landau, featuring a conformal manifold of $θ_{B}$ -dependent universality classes with an exactly marginal operator related to baryon density.
↳ hep-thhep-lathep-phnucl-thPRL(2026)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE