Nuclear Theory·nucl-th

Friday·March 13, 2026

13 papers—3 primary·10 cross-listed

01
Gamow-Teller strength of $^{12, 14, 16}$ C within deformed quasiparticle random-phase approximation
Eunja Ha · Myung-Ki Cheoun · H. Sagawa · Gianluca Colò
We investigate the Gamow-Teller (GT) transition strength distributions in the light carbon isotopes $^{12, 14, 16}$ C within the framework of the deformed quasiparticle random-phase approximation (DQRPA). Nuclear deformation is explicitly incorporated through Skyrme Hartree-Fock mean-field calculations combined with the QRPA formalism. The residual particle-hole $(p - h)$ and particle-particle $(p - p)$ interactions are derived from Brückner $G$ -matrix calculations based on the CD-Bonn potential, and their impact on the low-lying GT strengths is systematically examined by varying the corresponding interaction strengths. We find that nuclear deformation, associated with a reduced spin-orbit strength, plays a significant role in interpreting the GT strength distribution of $^{12}$ C. In contrast, the calculated GT $^{(-)}$ strength distribution of $^{14}$ C in the spherical limit reproduces the essential features of the experimental $(p, n)$ charge-exchange data. The case of $^{16}$ C reveals additional high-lying GT strength associated with deformation-induced configuration mixing.
nucl-th0 citations
02
Impact of octupole correlation on the inverse quasifission in $^{160} Gd +^{186} W$ collisions
Zhenji Wu · Xiang-Xiang Sun · Lu Guo
Multinucleon transfer (MNT) reactions offer a promising pathway to synthesize neutron-rich heavy nuclei, but the mechanism of inverse quasifission, as a key reaction channel of MNT, still remains not well understood. We employ time-dependent Hartree-Fock theory to investigate the reaction mechanism, especially the role of the octupole deformed shell in the MNT reaction of $^{160} Gd +^{186} W$ . The results show that inverse quasifission occurs when the deformed projectile and target collide in near tip-tip and tip-side orientations, which favors production of neutron-rich transtarget nuclei. Interestingly, the distributions and single-particle spectra of primary products reveal that the $N = 88$ octupole deformed shell in light fragments dominates inverse quasifission instead of the spherical shells of $^{208} Pb$ at a center-of-mass energy of $502.6 MeV$ , thus explaining the experimental observation that the yields of the transtarget products are enhanced in the Au region. Further exploration finds that quantum shell effects in inverse quasifission exhibit energy dependence. These results demonstrate that the octupole deformed shell plays a crucial role in the inverse quasifission dynamics, significantly advancing the understanding of the MNT reaction mechanism.
nucl-thPRC(2026)·4 citations
03
The Matter Radius of 132Sn and the CREX-PREX Dilemma
J. Piekarewicz
The density dependence of the nuclear symmetry energy remains a central open problem in nuclear physics. Parity violating electron scattering experiments have provided largely model-independent determinations of the neutron skin thickness of both 48Ca and 208Pb, whose consistent theoretical interpretation remains challenging. A new measurement of the matter radius of the unstable, doubly magic nucleus 132Sn provides an important additional constraint. Using a representative set of covariant energy density functionals spanning a wide range of isovector properties, we show that at least one of these models can simultaneously reproduce the charge and matter radii of132Sn. When interpreted together with the PREX and CREX results, the new measurement--much like CREX--favors a relatively soft symmetry energy. These findings underscore the need for an independent confirmation of the PREX result, such as the anticipated MREX campaign at the MESA facility.
nucl-thnucl-ex2 citations
04
Isentropic thermodynamics across the hadron-quark mixed phase in a two-phase model with a PNJL quark description
Eduardo L. G. Salgado🇵🇹 · Pedro Costa🇵🇹 · Constança Providência🇵🇹
We study the hadron-quark mixed phase within a two-phase model for symmetric and asymmetric matter. For the quark sector we employ the (2+1) Polyakov-extended Nambu-Jona-Lasinio model (PNJL) with vector interactions. We investigate how the hadronic equation of state affects the phase diagram and the thermodynamic properties inside the mixed phase. The behavior of isentropic trajectories in the mixed phase depends on the fixed entropy per baryon ( $s / ρ_{B}$ ), with trajectories near the critical end point (CEP) exhibiting a pronounced cooling pattern, while isentropic trajectories with low entropy per baryon undergo pronounced heating as the baryonic density increases. The adiabatic squared speed of sound displays characteristic peak and dip structures that depend on $s / ρ_{B}$ . The polytropic index along isentropic and isothermal trajectories, including in the vicinity of the CEP are also investigated. The effects of vector interactions and isospin asymmetry on thermodynamic observables likewise depend on the chosen $s / ρ_{B}$ value. Finally, we discuss the population of hyperons along isentropic trajectories and their influence on the phase diagram. The main effect of hyperons is to shift the onset of deconfinement to larger densities and decrease the density extension of the mixed phase.
↳ hep-phnucl-thPRD(2026)·0 citations
05
Cross-Environment Diagnostics for New Physics in Proton-Proton and Heavy-Ion Collisions
Yi Yang🇹🇼
Proton-proton and heavy-ion measurements are usually interpreted within separate theoretical and experimental frameworks, even when the same reconstructed final state is measured and the $pp$ result provides or constrains the elementary reference for nuclear observables. This separation creates a potential blind spot: an omitted contribution can be absorbed into production or signal-model parameters in $pp$ collisions and then be reinterpreted through independent nuclear-medium parameters in heavy-ion collisions. We propose cross-environment closure as a complementary search principle. Conventional parameters remain specific to each collision system, while one candidate new-physics contribution must remain coherent across systems and observables. Quarkonium is used as a controlled illustration rather than as the definition of the method. A near-degenerate dimuon component is shown to be absorbable into a retuned $pp$ spectrum and a single-peak mass fit, while the same $p_{T}$ -dependent contribution propagates into representative $R_{p A}$ , $R_{AA}$ , and $v_{2}$ relations. These quantities are consistency observables, not assumed new-physics baselines. The numerical examples are stress tests, not claims about an allowed particle or an anomaly in current data. The main result is a transferable diagnostic principle, illustrated here with quarkonium rather than formulated as a universal statistical framework.
↳ hep-phhep-exnucl-exnucl-th0 citations
06
Phase structure and observables at high densities from first principles QCD
Christian S. Fischer🇩🇪 · Jan M. Pawlowski🇩🇪
We provide a short review of the progress made in the past decade with functional QCD in the description of the phase structure of QCD. We summarise the most important technical aspects of the framework, discuss strategies for truncations and address the problem of systematic error estimates. We detail efforts to gauge the approach systematically with lattice QCD at zero chemical potential, also including the physics of the Columbia plot at non-physical quark masses. Our main focus is, however, the high density regime of QCD. We address the predictive power of the functional approach for the appearance of new phases beyond the chiral crossover regime for chemical potentials $μ_{B} / T \geq 4.5$ . The onset of this regime may be signalled by a critical end point of the crossover line but may also involve a moat regime or the emergence of an instability that indicates an inhomogeneous phase. Respective results include estimates for the location of the onset of new phases, and predictions for their experimental signatures.
↳ hep-phhep-exhep-latnucl-th20 citations
07
Dispersive Analysis of $D$ - and $B$ -Meson Form Factors with Chiral and Heavy-Quark Constraints
Simon Mutke🇩🇪 · Leon A. Heuser🇩🇪 · Ingrid Dax🇩🇪 · Bastian Kubis🇩🇪 · Stefan Leupold🇸🇪
We analyze the isovector vector form factors of $D$ , $D^{*}$ , $B$ , and $B^{*}$ mesons at low energies. We employ all constraints due to chiral and heavy-quark symmetry, and include the physics of resonant pion-pion rescattering in a model-independent way, using dispersion theory. Special attention is paid to the analytic properties of these form factors, which include anomalous thresholds due to triangle diagrams that are located on the physical Riemann sheets in some of the form factors. We extract the couplings of the $ρ (770)$ resonance to all these heavy mesons by determining the appropriate pole residues.
↳ hep-phhep-exnucl-thEPJC(2026)·1 citation
08
Comprehensive Effective Field Theory Analysis for Baryon Number Violating Processes
Chuan-Qiang Song🇨🇳 · Jiang-Hao Yu🇨🇳
Baryon number-violating processes arise generically in many extensions of the Standard Model, with Grand Unified Theories providing the most compelling realizations. Ongoing experimental searches at JUNO, Hyper-K, and DUNE motivate a more precise and model-independent analysis utilizing the effective field theory (EFT) framework capable of connecting ultraviolet dynamics to low-energy hadronic observables. In this work, we perform a pipeline analysis that connects baryon number-violating (BNV) new physics to its low-energy description through the Standard Model EFT (SMEFT) up to dimension nine and the Low-Energy EFT (LEFT) up to dimension eight, and subsequently matches onto chiral perturbation theory using a systematic spurion method. We show that the complete set of dimension-eight LEFT operators enables the inclusion of the full set of chiral representations for three-quark operators with derivatives, which are also embedded in the chiral Lagrangian after quark-hadron matching. By contrast, the conventional dimension-six operators generate only the $(3 ˉ, 3)$ and $(8, 1)$ representations. The higher dimensional LEFT operators should be matched from higher order SMEFT operators, and thus a wider class of UV completions are allowed. We consider the complete tree-level UV resonances for dimension 6 and 7 SMEFT operators, and representative UVs for higher dimension operators.
↳ hep-phnucl-th1 citation
09
Transverse Structure of the Kaon: A light-front Hamiltonian Approach
Yuanqi Lu🇨🇳 · Zhimin Zhu🇨🇳 · Jiangshan Lan🇨🇳 · Chandan Mondal🇨🇳 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸
We employ the Basis Light-Front Quantization (BLFQ) framework to compute the leading-twist (twist-2) and subleading-twist (twist-3) transverse-momentum-dependent parton distribution functions (TMDs) of the kaon. The light-front wave functions are obtained by diagonalizing a light-front QCD Hamiltonian that includes quark-antiquark (|q\bar{q}\rangle) and quark-antiquark-gluon (|q\bar{q}g\rangle) Fock components together with a three-dimensional confinement. Using the QCD equations of motion, the twist-3 TMDs are decomposed into twist-2 constributions and genuine twist-3 terms, the latter encoding quark-quark-gluon correlations beyond the probabilistic picture. These genuine twist-3 constributions arise from the interference between the |q\bar{q}\rangle and |q\bar{q}g\rangle sectors, which are usually negelected in the Wandzura-Wilczek approximation. This work provides the first theoretical predictions of kaon subleading-twist TMDs that explicitly account for Fock-sector interference. In addition, we present results for the kaon's twist-2 and twist-3 collinear parton distribution functions (PDFs). The twist-2 PDFs are found to be in good agreement with the recent global analysis by the JAM collaboration.
↳ hep-phhep-thnucl-th1 citation
10
Energy-momentum tensor form factors and spin density distribution in the nucleon calculated in a quantized Skyrme model with vector mesons
Kenji Fukushima🇯🇵 · Tomoya Uji🇯🇵
We investigate energy-momentum tensor (EMT) form factors and the spatial spin density distribution in the nucleon within a framework of the quantized Skyrme model with vector mesons. We construct both the canonical and Belinfante improved EMTs and analyze how pseudogauge uncertainty influences local spin and momentum densities while leaving the global nucleon properties unchanged. Using the inversion formulas from nucleon matrix elements in the forward limit, we extract the form factors, $A (t)$ , $D (t)$ , and $J (t)$ , in both pseudogauges and the additional antisymmetric form factor associated with the canonical EMT. We find that the pseudogauge choice leads to sizable differences in the local spin and momentum densities. In particular, the canonical EMT naturally encodes spin density through the antisymmetric tensor structure, while the Belinfante EMT is sensitive to the total angular momentum only. Our results illustrate explicitly how different pseudogauges correspond to different spatial interpretations of nucleon spin structure within the same underlying dynamics. These findings provide a concrete model realization of the pseudogauge ambiguity in QCD-inspired nucleon structure and offer useful intuition for interpreting spatial distributions.
↳ hep-phnucl-thPRD(2026)·5 citations
11
Universality Emerging in a Universality: Derivation of the Ericson Transition in Stochastic Quantum Scattering and Experimental Validation
Simon Köhnes · Jiongning Che · Barbara Dietz · Thomas Guhr
At lower energies, the resonances in scattering experiments are often isolated. In quantum chaotic many-body, disordered or generically stochastic systems, the resonances overlap at larger energies. Eventually, the Ericson regime is reached in which the cross section behaves like a random function. The scattering-matrix elements then follow a universal Gaussian distribution. For more than sixty years, the emergence of this robust additional universal behavior on top of the universal system stochasticity has awaited a concise analytical treatment. We derive the transition to the Ericson regime in the universal Heidelberg approach and prove the universal Gaussian distribution by a proper asymptotic expansion. We also obtain explicit formulae for the moments of the distributions. We compare with microwave experiments and numerical simulations.
↳ cond-mat.stat-mechnucl-thphysics.atom-phPRL(2026)·1 citation
12
Schwinger Model with a Dynamical Axion
Gabriel Rouxinol🇩🇪 · Tom Magorsch🇩🇪 · Jesse J. Osborne🇩🇪 · Nora Brambilla🇩🇪 · Jad C. Halimeh🇩🇪
One of the major open puzzles in the Standard Model of particle physics is the strong CP problem: although Quantum Chromodynamics allows a CP-violating topological $θ$ -term, experiments constrain its value to be extremely small. The Peccei--Quinn mechanism resolves this problem by promoting the $θ$ -angle to a dynamical field-introducing the axion -- whose dynamics relax the effective angle $θ_{eff}$ to a CP-conserving minimum. Here, we investigate the resulting axion physics in a Hamiltonian lattice gauge theory (LGT) by coupling a quantized axion field to the massive Schwinger model with a topological $θ$ -term. Using infinite matrix product state techniques, we compute the ground-state properties of the resulting theory and demonstrate that the axion dynamically relaxes $θ_{eff}$ to the minimum of the vacuum energy. Consequently, the ground-state energy becomes independent of $θ$ , demonstrating the axion-mediated solution to the strong CP problem within a fully dynamical LGT. We further analyze CP restoration and extract the axion mass from the topological susceptibility and excitation spectrum. Our results provide a nonperturbative demonstration of axion dynamics in a quantum LGT amenable to investigation on modern quantum hardware.
↳ hep-phcond-mat.quant-gashep-lathep-th+13 citations
13
$D ˉ$ -meson Nucleon Scattering from Lattice QCD at the Physical Point
Wren Yamada🇯🇵 · Yan Lyu🇯🇵 · Kotaro Murakami🇯🇵 · Takumi Doi🇯🇵
We report the first lattice QCD study of the $s$ -wave scattering of the $D ˉ$ -meson and the nucleon at the physical point, utilizing (2+1)-flavor configurations generated by the HAL QCD collaboration with a pion mass of $m_{π} ≃ 137$ MeV and a lattice spacing of $a ≃ 0.084$ fm. By applying the HAL QCD method to the four-point correlation function of the $D ˉ N$ system, we obtain a leading-order potential of the derivative expansion of the interaction kernel, which is then used to extract the $s$ -wave phase shifts of low-energy $D ˉ N$ scattering. Both the isospin $I = 0$ and $I = 1$ channels have a short-range repulsive core and a shallow attractive pocket in the intermediate to long-range region, though the $I = 0$ channel is more attractive than the $I = 1$ channel. We also observe that the $D ˉ N$ potential exhibits more attraction than the $K N$ potential, which is its analog in the strange sector. In terms of the $s$ -wave phase shifts, the $I = 0$ channel shows a weak attractive behavior in the low-energy region with a positive scattering length of $0.246 \pm 0.105 (_{- 0.051}^{+ 0.084})$ fm, whereas the $I = 1$ channel shows repulsion with a negative scattering length of $- 0.086 \pm 0.050 (_{- 0.001}^{+ 0.037})$ fm. No bound states are found in both isospin channels, indicating the absence of a pentaquark state in the $s$ -wave $D ˉ N$ system.
↳ hep-lathep-phnucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE