Nuclear Theory·nucl-th

Monday·February 2, 2026

10 papers—3 primary·7 cross-listed

01
[Submitted on 29 Jan 2026]
Low-energy 17O(n,g)18O reaction within the microscopic potential model and its role for the weak r-process
Nguyen Le Anh · Jasmine Sarahi Andrews · Bui Minh Loc · Andre Sieverding
The neutron radiative capture reaction $^{17}$ O(n, $γ$ )18O plays a pivotal role in both nuclear structure studies and astrophysical nucleosynthesis, particularly in the formation of elements during hydrostatic and explosive stellar environments. We calculated the $^{17}$ O(n, $γ$ ) $^{18}$ O cross section within the Skyrme Hartree-Fock potential model and analyzed electric dipole E1 transitions to both positive and negative-parity states below the alpha-decay threshold in $^{18}$ O. Our cross sections are significantly different from the data available in commonly used libraries. We further investigate the impact of the new calculated cross section on weak r-process nucleosynthesis using large-scale reaction network calculations across a wide range of electron fractions and entropies. Our results show that the $^{17}$ O(n, $γ$ ) $^{18}$ O reaction rate significantly influences the production of first r-process peak elements, such as strontium, under specific astrophysical conditions. This study highlights the importance of accurate nuclear dat$ for light isotopes in modeling heavy-element synthesis and provides updated reaction rates for future nucleosynthesis simulations.
Comments:
11 pages, 12 figures, submitted to Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.22234 [pdf]
PRC(2026)·0 citations
02
[Submitted on 30 Jan 2026]
Enhanced Yield Rate of \textsuperscript{229m}Th via Cascade Decay in Storage Rings and Electron Beam Ion Traps
Yumiao Wang · Yi Yang · Yixin Li · Ding Yue · Kai Zhao · Youjing Wang · Changbo Fu · Yugang Ma
The low-energy nuclear isomeric state of \textsuperscript{229m}Th provides a unique bridge between nuclear and atomic physics, enabling applications such as nuclear clocks and precision metrology. However, efficient and controllable production of \textsuperscript{229m}Th remains a major experimental challenge. We propose an efficient scheme to produce the $^{229 m}$ Th in storage rings (SRs) and electron beam ion traps (EBITs), using a cascade decay pathway. Highly charged ions are excited to higher nuclear states via nuclear excitation by inelastic electron scattering (NEIES) and nuclear excitation by electron capture (NEEC), followed by radiative or internal conversion cascades that populate the isomer. Our calculations demonstrate that, under typical SRs and EBITs conditions, optimized indirect excitation pathways significantly enhance \textsuperscript{229m}Th production rate. In particular, NEIES can provide an enhancement of up to four orders of magnitude through cascade de-excitation at high energies, while NEEC can contribute an additional enhancement of up to several tens of times. Such a significant increase in the \textsuperscript{229m}Th yield rate would facilitate its application in various nuclear photonics fields, especially in the development of atomic nuclear clocks.
Comments:
9 pages, 6 figures, and 3 tables
Subjects:
Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2601.22417 [pdf]
PRC(2026)·2 citations
03
[Submitted on 30 Jan 2026]
$f_{2} (1270) \to π + π$ as a probe of spin and vorticity in heavy-ion collisions
In Woo Park🇰🇷 · Beomkyu Kim🇰🇷 · Giorgio Torrieri🇧🇷 · Kayman J. Gonçalves🇧🇷 · Sanghoon Lim🇰🇷 · Su Houng Lee🇰🇷
The correlation between vorticity and spin alignment in heavy-ion collisions can be probed through polarization measurements of hadrons, whose total spin originates from both constituent-quark spins and orbital angular momentum in the quark-model framework. To motivate such experimental studies, we calculate the general angular distribution of produced pion in $f_{2} (1270) \to π + π$ using interaction Lagrangian and helicity formalism and check that both methods yield the same result. The distribution is given as a function of angle between pion and initial quantization axis of $f_{2}$ and the spin density matrix element of $f_{2}$ . Its diagonal entries and $ρ_{20}$ component were computed assuming local thermal equilibrium and blast wave model for different centrality classes, hence given as a function of azimuthal angle with respect to the impact parameter.
Comments:
13 pages, 23 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2601.22898 [pdf]
0 citations
04
[Submitted on 29 Jan 2026] (cross-list from hep-ph)
Azimuthal angular entanglement between decaying particles in ultra-peripheral ion collisions
Spencer R. Klein🇺🇸
Ultra-peripheral collisions (UPCs) involving relativistic heavy ions are a unique laboratory to study quantum correlations. The intense electromagnetic fields generate high rates of photonuclear interactions, including events involving multiple photon exchange. Multiple photon exchange can result in the production of multiple vector mesons and/or nuclear excitations. These interactions share a common impact parameter, so the photons have the same linear polarization. The shared polarization entangles the particles, leading to unique quantum correlations. The decays of these vector excitations are sensitive to this polarization, allowing for the study of these correlations. This letter will compare classical and quantum calculations of the correlations between these azimuthal directions. The two approaches predict vert different angular correlations. The differences are akin to those seen with polarized photons in tests of Bells inequality. Uniquely, UPC photoproduction can produce final states containing three or more particles, all entangled with the same polarization. These more complex states exhibit additional unique phenomenology, allowing new tests of multi-particle entanglement.
Comments:
Submitted for publication. Comments welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2601.22212 [pdf]
1 citation
05
[Submitted on 29 Jan 2026] (cross-list from hep-lat)
Excited-state uncertainties in lattice-QCD calculations of multi-hadron systems
William Detmold🇺🇸 · Anthony V. Grebe🇺🇸 · Daniel C. Hackett🇺🇸 · Marc Illa🇺🇸 · Robert J. Perry🇺🇸 · Phiala E. Shanahan🇺🇸 · Michael L. Wagman🇺🇸
Excited-state effects lead to hard-to-quantify systematic uncertainties in lattice quantum chromodynamics (LQCD) spectroscopy calculations when computationally accessible imaginary times are smaller than inverse excitation gaps, as often arises for multi-hadron systems with signal-to-noise problems. Lanczos residual bounds address this by providing two-sided constraints on energies that do not require assumptions beyond Hermiticity, but often give very conservative systematic uncertainty estimates. Here, a more-constraining set of gap bounds is introduced for hadron spectroscopy. These bounds provide tighter constraints whose validity requires an explicit assumption about an energy gap. Exactly solvable lattice field theory correlators are used to test the utility of residual and gap bounds at finite and infinite statistics. Two-sided bounds and other analysis methods are then applied to a high-statistics LQCD calculation of nucleon-nucleon scattering at $m_{π} \sim 800$ MeV. Generalized eigenvalue problem (GEVP) and Lanczos energy estimators are compatible when applied to the same correlator data, but analyses including different interpolating operators show statistically significant inconsistencies. However, two-sided bounds from all operators are consistent. Under the assumption that the number of energy levels below $N Δ$ and $ΔΔ$ thresholds is the same as for non-interacting nucleons, gap bounds are sufficient to constrain nucleon-nucleon scattering amplitudes at phenomenologically relevant precision. Lanczos methods further reveal that energy-eigenstate estimates from previously studied asymmetric correlators have not converged over accessible imaginary times. Nevertheless, data-driven examples demonstrate why assumptions are required to draw conclusions about the natures of two-nucleon ground states at these masses.
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.22272 [pdf]
3 citations
06
[Submitted on 29 Jan 2026] (cross-list from hep-lat)
Excited-state uncertainties in lattice-QCD calculations of hadron masses and scattering phase shifts
William Detmold🇺🇸 · Anthony V. Grebe🇺🇸 · Daniel C. Hackett🇺🇸 · Marc Illa🇺🇸 · Robert J. Perry🇺🇸 · Phiala E. Shanahan🇺🇸 · Michael L. Wagman🇺🇸
Lattice QCD has historically produced energy results interpretable as either estimates relying on implicit assumptions about asymptotic behavior or one-sided upper bounds. New Lanczos methods providing two-sided bounds with less-restrictive assumptions are introduced and quantified in a high-statistics calculation with unphysical quark masses. Two-sided bounds without spectral assumptions provide sub-percent constraints on the nucleon mass. Other bounds, which assume all states in a given energy window are resolved, provide meaningful two-sided constraints on nucleon-nucleon scattering phase shifts.
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.22273 [pdf]
1 citation
07
[Submitted on 30 Jan 2026] (cross-list from hep-th)
Entanglement in Elastic and Inelastic Two-particle Scatterings at High Energy
Robi Peschanski🇫🇷 · Shigenori Seki🇯🇵
We study the entanglement produced in transverse momentum by two-particle scattering at high energy. Employing the S-matrix framework for the derivation of reduced density matrices, we formulate the entanglement entropy for an inelastic scattering as well as an elastic one. We display the formulas of the entanglement entropy in terms of two-body cross sections. We also derive the entanglement density as a function of the transverse momentum. As an application, we then focus on both forward elastic ( $p n \to p n$ ) and inelastic ( $p n \to n p$ ) channels scattering allowing for a fruitful comparison of the two reactions with the same proton-neutron content. We evaluate the elastic and inelastic entanglement entropy by using known parameterizations of experimental data for neutron-proton reactions. Comparing those entanglement entropies, we observe that the inelastic scattering produces more overall entanglement than the elastic one in the $p n$ sector.
Comments:
25 pages, 6 figures; v2: 26 pages, typos corrected, comments added in Secs. 3.3, 3.4 and C.3
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.22502 [pdf]
PRD(2026)·4 citations
08
[Submitted on 30 Jan 2026] (cross-list from hep-ph)
Multiquark bound states and resonances
Jean-Marc Richard🇫🇷 · Alfredo Valcarce🇪🇸 · Javier Vijande🇪🇸
We review the chromoelectric and chromomagnetic mechanisms that tentatively lead to stable or metastable multiquark configurations. An alternative interpretation of the dynamics is the quark interchange between hadrons, as illustrated in the case of the fully-charm systems.
Comments:
6 pages, Proc. Hadron 2025, Osaka, Japan, March 27-31, 2025
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.22842 [pdf]
PoS(2026)·0 citations
09
[Submitted on 30 Jan 2026] (cross-list from hep-ph)
Heavy quark polarization anisotropy as a novel probe of fireball geometry
Amaresh Jaiswal🇮🇳
We propose a new approach to probe the initial fireball geometry in relativistic heavy-ion collisions using spin polarization. Specifically, we introduce polarization harmonics of open heavy hadrons as a novel observable sensitive to geometric anisotropies. Heavy quarks are produced in early hard scatterings and can acquire spin polarization from the strong, transient electromagnetic fields present at early times. As they propagate through the anisotropic quark-gluon plasma, medium-induced interactions lead to path-length dependent depolarization, imprinting an azimuthally anisotropic polarization pattern. Within the framework of rotational Brownian motion, we show that the resulting polarization harmonics are directly related to the initial spatial eccentricities, thereby establishing heavy-flavor polarization anisotropies as a sensitive and complementary probe of the early-time collision geometry. We present quantitative estimates of the second (elliptic) polarization harmonic associated with the recently observed $D^{*+}$ spin alignment reported by the ALICE Collaboration.
Comments:
9 pages, 1 figure, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.22882 [pdf]
PLB(2026)·2 citations
10
[Submitted on 30 Jan 2026] (cross-list from hep-ph)
Analysis of regulator and cutoff artifacts in the phase diagram of the quark-meson model
Jonas Stoll🇩🇪 · Niklas Zorbach🇩🇪 · Lutz Kiefer🇩🇪 · Fabrizio Murgana🇩🇪 · Jens Braun🇩🇪 · Dirk H. Rischke🇩🇪
We study regulator and cutoff artifacts in the quark-meson model at finite temperature and quark chemical potential within the functional renormalization-group approach using the local potential approximation. To this end, we discuss the concept of renormalization-group consistency in effective models, which necessitates a nontrivial parameter-fixing procedure to enable a meaningful comparison of results obtained with different regulators and cutoffs. We employ a standard range of cutoff values used in phenomenological studies and regulators that differ significantly in their analytic properties as well as in their classification according to the principle of strongest singularity. We find that regulator and cutoff dependences are small at low temperatures and quark chemical potentials. At high temperatures and low quark chemical potentials, significant cutoff artifacts arise, whereas the properties of the regulator affect the dynamics in the regime governed by a chiral phase transition of first order at low temperatures and high quark chemical potentials.
Comments:
15 pages, 8 figures, 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.23005 [pdf]
1 citation

Affiliations

first authorsco-authorsvia INSPIRE