Nuclear Theory·nucl-th

Friday·April 3, 2026

13 papers—5 primary·8 cross-listed

01
[Submitted on 2 Apr 2026]
Long-standing problem: The nuclear level density angular-momentum dependence and isomeric data assessment
M. Avrigeanu🇷🇴 · E. Šimečková🇨🇿 · J. Mrázek🇨🇿 · X. Ledoux🇫🇷 · J. Novak🇨🇿 · M. Štefánik🇨🇿 · M. Ansorge🇨🇿 · A. Cassisa🇨🇿 · J. Kozic🇨🇿 · C. Costache🇷🇴 · V. Avrigeanu🇷🇴
Recent 91,92,93Tc activation for deuterons incident on natMo has become a challenge for the nuclear level density (NLD) angular-momentum dependence. Actually, replacement of the moment of inertia rigid-body value Ir by half of it, within a given NLD parameter set, demands a change of the rest of NLD parameters significantly beyond their fitted limits. The corresponding uncertainty of calculated cross sections versus the NLD parameter accuracy is also higher, while use of either the same or distinct compound-nucleus and preequilibrium emission spin distributions becomes significant at higher incident energies. Nevertheless, the current way to describe experimental isomeric cross sections by using at most half of Ir values provides agreement of the measured and calculated data at the price of less and less correct NLDs. The moment of inertia relevance for the NLD correctness also emphasizes the value of a direct method to endorse it. Further measurements of average resonance spacings of s-wave neutrons and protons, corresponding to different spins of the same nucleus, are therefore highly demanded.
Comments:
14 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2604.01648 [pdf]
PRResearch(2026)·0 citations
02
[Submitted on 2 Apr 2026]
Collective quantum tunneling with time-dependent generator coordinate method
Wenmin Deng · Guangping Chen · Ganlong Ding · Sibo Wang · Jing Peng · Haozhao Liang
Inspired by the work of McGlynn and Simenel [Phys. Rev. C {\bf 102}, 064614 (2020)], this study investigates the quantum tunneling of two interacting distinguishable particles in two potential wells. We first benchmark the system by reproducing key established results: the exact quantum solution and the spurious self-trapping effect that arises in the real-time mean-field dynamics for strong interactions. To exactly capture the tunneling dynamics, we apply the time-dependent generator coordinate method (TDGCM) to the model. Numerical simulations demonstrate that the TDGCM, by utilizing the real-time mean-field states as generator states, successfully overcomes the self-trapping effect, yielding tunneling dynamics in excellent agreement with the exact solution. Furthermore, we explore the expectation values of the generator coordinates from the correlated TDGCM many-body wave function. While different methods for calculating expectation values show consistent results in some cases, significant discrepancies are observed in others, providing critical insights into the emergence of collective and single-particle behaviors in interacting systems. This work also verifies the TDGCM as a robust framework for describing collective quantum tunneling and opens avenues for its application to more complex and realistic systems.
Comments:
12 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2604.01906 [pdf]
1 citation
03
[Submitted on 2 Apr 2026]
Gauge invariant momentum broadening of hard probes in glasma
Margaret E. Carrington🇨🇦 · Bryce T. Friesen🇨🇦 · Stanislaw Mrowczynski🇵🇱
We compute the transport coefficient $q^$ which quantifies the transverse momentum broadening of hard probes passing through the evolving glasma from the earliest stage of relativistic heavy-ion collisions. We use a proper-time expansion method which is designed to study the glasma at very early times. In our earlier calculations of $q^$ we used an approximation that greatly simplifies the complexity of the calculation but introduces a violation of gauge invariance. Based on these results we argued that the glasma plays an important role in jet quenching. In this paper we have used a gauge invariant formulation to calculate $q^$ . The results for the momentum broadening coefficient are quantitatively very close to those of our previous simplified version of the calculation and confirm our earlier conclusion about the importance of the glasma contribution to jet quenching.
Comments:
21 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2604.02050 [pdf]
PRC(2026)·3 citations
04
[Submitted on 2 Apr 2026]
Chiral-scale effective field theory for dense and thermal systems
Yong-Liang Ma🇨🇳
In this contribution, I will present some properties of nuclear matter (NM) by using the chiral-scale effective field theory that is anchored on the chiral, scale and hidden local flavor symmetries of QCD. We show that the sound velocity (SV) of the compact star matter can saturate the conformal limit, the SV exhibits a peak configuration in the intermediate density. To extend the chiral-scale effective field theory to both dense and tnermal systems, we setup a chiral-scale density counting (CSDC) rule and explore the contributions up to $O (k_{c}^{12})$ .
Comments:
Contribution to Excited QCD 2026 Workshop, Granada, Spain, 2026.01.08-01.14
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2604.02098 [pdf]
Acta Phys.Polon.Supp.(2026)·1 citation
05
[Submitted on 2 Apr 2026]
Formal definition of intrinsic collectivity in the continuum via Takagi factorization of the Jost-RPA S-matrix residue
Kazuhito Mizuyama
A formal and systematic framework is proposed to quantify the intrinsic collectivity of resonance states in the continuum, independent of their extrinsic manifestation in the strength function. By integrating Takagi factorization into the Jost-RPA framework, we utilize the rank-1 property of the S-matrix residue at a resonance pole to uniquely decompose it into microscopic transition amplitudes for each configuration. To evaluate the nature of these modes, we introduce the Intrinsic Coherence Index ( $C^{(n)}$ ) and the Collective Phase ( $Θ^{(n)}$ ), which characterize the dynamical phase synchronization and the line-shape orientation, respectively. Furthermore, a unified Total Collectivity Index ( $R^{(n)}$ ) is defined by combining the coherence index with the Normalized Participation Ratio ( $η^{(n)}$ ). Applying this framework to the isoscalar $2^{+}$ , isovector $2^{+}$ , and $E 1$ excitations in $^{16}$ O, we demonstrate that the intrinsic collectivity is decoupled from the observable line shape. Our analysis identifies "hidden" collective modes -- states with high internal synchronization that do not appear as prominent peaks -- and clarifies that distorted structures or dips can either be highly collective or non-collective depending on their microscopic phase alignment. This approach provides a well-defined structural basis for investigating many-body excitations in open quantum systems and nuclei near the drip lines.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2604.02237 [pdf]
0 citations
06
[Submitted on 31 Mar 2026] (cross-list from hep-ph)
Origin of the Covariant Wigner Operator as a Quantum Amplitude in QCD
Chueng-Ryong Ji🇺🇸 · Daniel W. Piasecki🇺🇸
The Wigner function plays a central role in QCD as a phase space object encoding correlations among quarks, antiquarks, and gluons, yet its interpretation remains subtle due to its quasiprobabilistic nature and possible negativity. Recent work based on the Koopman-von Neumann-Sudarshan (KvNS) Hilbert space formulation of classical mechanics suggests the Wigner function arises as a quantum probability amplitude projected onto classical phase space, rather than a quasiprobability density (Bondar et al., 2013; McCaul et al., 2023). In the classical limit, this amplitude reduces to the classical Koopman wavefunction. In this work, we extend this perspective to relativistic QCD by constructing a Koopman description of the quark Wigner operator. We show that the Wigner operator is naturally isomorphic to a phase space spinor, providing a unified framework in which both classical and quantum dynamics are expressed. Within this formulation, the Wigner function retains its interpretation as an amplitude even in the relativistic regime. This viewpoint clarifies the origin of negativity and other nonclassical features, and provides a more transparent foundation for parton distribution functions in QCD. Remarkably, the relativistic Koopman framework reproduces the classical limit of QCD.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2604.01248 [pdf]
Symmetry(2026)·0 citations
07
[Submitted on 1 Apr 2026] (cross-list from hep-ph)
Mechanical Equilibrium in the Magnetized Quark--Hadron Mixed Phase: A Covariant Generalization of the Gibbs Condition
Aric Hackebill🇺🇸
We formulate a covariant mechanical equilibrium condition for the quark-hadron mixed phase boundary in the presence of a magnetic-field-induced pressure anisotropy. Using the \emph{relativistic thin-shell} formalism to describe the quark-hadron boundary, we interpret conservation of stress-energy across the interface as a set of generalized Young--Laplace conditions which characterize the geometry of the interface. In a comoving stationary frame, this provides a covariant description of mechanical equilibrium at the interface, which serves as a replacement for the scalar pressure-balance condition used in the isotropic Gibbs construction.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2604.01253 [pdf]
Universe(2026)·0 citations
08
[Submitted on 1 Apr 2026] (cross-list from hep-ph)
Reconciling hadronic and partonic analyticity in $b \to s ℓℓ$ transitions
Martin Hoferichter🇨🇭 · Bastian Kubis🇩🇪 · Simon Mutke🇩🇪
Rare $B$ -meson decays mediated by $b \to s ℓℓ$ transitions constitute sensitive probes of physics beyond the Standard Model, and have triggered considerable interest due to hints for deviations from the Standard-Model prediction. To establish a discrepancy beyond a reasonable doubt, control over the nonlocal matrix elements involving charm loops is essential, which, for large spacelike virtualities, can be constrained by an operator product expansion with coefficients known at two-loop order. We observe that the analytic structure of this partonic calculation, whose understanding is important to put forward rigorous parameterizations, follows from simple triangle topologies and demonstrate explicitly how dispersion relations are fulfilled even in the case of anomalous thresholds. Crucially, these anomalous contributions match onto the ones expected when considering hadronic degrees of freedom, proving that the partonic calculation does not miss anomalous effects and justifying its use in regions of parameter space in which a perturbative description applies.
Comments:
9 pages, 7 figures; v2 as published in Phys. Lett. B
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2604.01284 [pdf]
PLB(2026)·5 citations
09
[Submitted on 2 Apr 2026] (cross-list from nucl-ex)
Femtoscopy of Strange Baryons in Heavy-ion Collisions at RHIC-STAR
Boyang Fu (for the STAR Collaboration)🇨🇳
Studying the final state interactions and finding possible bound states is helpful for understanding the strong interactions and comprehending the equation-of-state (EoS) of the nuclear matter. In these proceedings, we present recent femtoscopy results of \pXi{}, \LaLa{}, \pOm{} femtoscopic correlations with high statistics Isobar (Ru+Ru, Zr+Zr) and Au+Au collisions measured by the STAR experiment. For the \pXi{} and \pOm{} pairs, the centrality dependence of source size and the scattering parameters are extracted with the Lednický-Lyuboshitz approach. The results show that there is an attractive interaction in \pXi{} pairs and a bound state in \pOm{} pairs.
Comments:
4 pages, 9 figures, Proceedings for INPC 2025
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2604.01660 [pdf]
EPJ Web Conf.(2026)·0 citations
10
[Submitted on 2 Apr 2026] (cross-list from hep-ph)
Tetraquark-Jet Systems at the High-Luminosity LHC
Francesco Giovanni Celiberto🇪🇸
We investigate the high-energy production of tetraquark-jet systems at the LHC and its forthcoming High-Luminosity upgrade. In this review, we examine the leading-power fragmentation of fully heavy tetraquarks ( $T_{4 Q}$ ) in hadronic collisions, highlighting their relevance as novel probes of multiquark dynamics in QCD. Our analysis relies on the hadron-structure-oriented TQ4Q1.1 fragmentation functions, built within a nonrelativistic QCD framework that incorporates both gluon- and heavy-quark-initiated channels. Threshold-consistent DGLAP evolution is performed through the HF-NRevo scheme, enabling a unified treatment of mass thresholds and scale variations. We also provide a systematic discussion of uncertainties arising from color-composite long-distance matrix elements (LDMEs) and from perturbative hard- and fragmentation-scale inputs (H- and F-MHOUs). Phenomenological predictions are obtained using the (sym)Jethad framework at NLL/NLO $^{+}$ accuracy for semi-inclusive tetraquark-jet production at the LHC and beyond. This review connects the emerging spectroscopy of fully heavy exotics with modern fragmentation-based approaches to hadron structure and high-energy QCD.
Comments:
45 pages, 10 figures, 1 table, 602 references. Invited review article
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.01865 [pdf]
Universe(2026)·6 citations
11
[Submitted on 2 Apr 2026] (cross-list from hep-ph)
Heavy-Flavor Fragmentation: The QCD Portal to Exotic Matter
Francesco Giovanni Celiberto🇪🇸
We investigate the core dynamics behind exotic matter formation via the TQ4Q1.1 set of collinear fragmentation functions for fully charmed or bottomed tetraquarks in three quantum configurations: scalar ( $0^{++}$ ), axial vector ( $1^{+-}$ ), and tensor ( $2^{++}$ ). We adopt leading-power single-parton fragmentation within a nonrelativistic QCD framework tailored to tetraquark Fock states. Initial-scale inputs are constructed from updated gluon- and heavy-quark channels, and evolved through threshold-consistent DGLAP within HF-NRevo. We present the first systematic propagation of uncertainties from color-composite long-distance matrix elements governing tetraquark hadronization. This study advances the connection between hadronic structure, precision QCD, and exotic matter.
Comments:
6 pages, 1 figure. Proceedings of the "Excited QCD 2026" Workshop, Universidad de Granada, Carmen de la Victoria (Spain), January 8-14, 2026
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.01867 [pdf]
Acta Phys.Polon.Supp.(2026)·3 citations
12
[Submitted on 2 Apr 2026] (cross-list from hep-ph)
Triply Heavy $Ω$ Baryons with JETHAD: A High-Energy Viewpoint
Francesco Giovanni Celiberto🇪🇸
We investigate the leading-power fragmentation of triply heavy $Ω$ baryons in high-energy hadronic collisions. Extending our previous work on the $Ω_{3 c}$ sector, we release the full OMG3Q1.0 family of collinear fragmentation functions by completing the description of the charm channel and delivering the novel $Ω_{3 b}$ functions. These hadron-structure-oriented functions are constructed from improved proxy-model calculations for heavy-quark and gluon fragmentation, matched to a flavor-aware DGLAP evolution based on the HF-NRevo scheme. For phenomenological applications, we employ the (sym)JETHAD multimodular interface to compute and analyze NLL/NLO $^{+}$ semi-inclusive $Ω_{3 Q}$ plus jet distributions at the HL-LHC and FCC. This work consolidates the link between hadron structure, rare baryon production, and resummed QCD at the energy frontier.
Comments:
45 pages, 7 figures, 555 references. Invited review article. Chapter V of the review pentalogy "Heavy hadrons with JETHAD: A high-energy viewpoint"
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.01871 [pdf]
Symmetry(2026)·8 citations
13
[Submitted on 2 Apr 2026] (cross-list from hep-lat)
Tackling inverse problems for PDFs from lattice QCD
Alexander Rothkopf🇰🇷
In this kick-off presentation for the "Recent developments in QCD" session at Baryons 2025 I will tie together the recent progress made on the extraction of parton distribution functions (PDFs) in lattice QCD and the long standing efforts in solving the inverse problem in the form of spectral function reconstruction.
Comments:
11 pages, 6 figures, invited talk given at the 2025 International Conference on the Structure of Baryons (Baryons 2025), Nov. 13th, ICC Jeju, South Korea
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2604.01996 [pdf]
J.Subatomic Part.Cosmol.(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE