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

Affiliations

first authorsco-authorsvia INSPIRE

Long-standing problem: The nuclear level density angular-momentum dependence and isomeric data assessment

Collective quantum tunneling with time-dependent generator coordinate method

Gauge invariant momentum broadening of hard probes in glasma

Chiral-scale effective field theory for dense and thermal systems

Formal definition of intrinsic collectivity in the continuum via Takagi factorization of the Jost-RPA S-matrix residue

Affiliations