Nuclear Theory·nucl-th

Wednesday·January 21, 2026

30 papers—13 primary·17 cross-listed

01
[Submitted on 16 Jan 2026]
Pauli Consistent $α$ -- $α$ Interaction from Inverse Scattering via Phase Function Wavefunctions and RGM Antisymmetrization
Anil Khachi · Shikha Awasthi · Tarachand Verma · Ranjana Joshi
The present study employs the phase function method (PFM) to construct scattering wavefunctions for the $α$ -- $α$ system, which is central to understanding the structure of $^{8} Be$ . The primary objective is to analyze scattering dynamics through the reconstruction of radial wavefunctions for the $ℓ = 0$ , 2, and 4 partial waves within the PFM framework, thereby avoiding direct numerical integration of the Schrödinger equation. Previously optimized single-term and two-term Morse potentials are used for benchmarking, while a double Gaussian (DG) potential is independently determined using a genetic algorithm. The resulting non-antisymmetrized wavefunctions are subsequently employed as input to the resonating group method (RGM), enabling the incorporation of Pauli exclusion effects. The antisymmetrized wavefunctions obtained in this manner show good agreement with earlier results reported by Hiura \textit{et al.} The quasi-bound state energy for the $ℓ = 0$ partial wave is evaluated using the matrix method and is found to be consistent with the experimental value of $0.08, (0.09)$ ~MeV. The analysis further indicates the presence of two Pauli-forbidden S-wave states, consistent with Levinson's theorem, while the positive-energy solution near $0.08 MeV$ corresponds to the physical $^{8} Be$ resonance. Scattering parameters extracted from the proposed interactions are in good agreement with NLO, NNLO, and empirical results. Overall, the results establish the effectiveness of the PFM-based framework for reconstructing scattering observables and provide further support for the robustness of phenomenological $α$ -- $α$ interaction models.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.11749 [pdf]
0 citations
02
[Submitted on 17 Jan 2026]
Nucleon Resonances in Nuclear Matter and Finite Nuclei
Horst Lenske🇩🇪
The theory of nuclear excitations involving nucleon resonances is revisited and significantly extended to asymmetric nuclear matter and higher P- and S-wave $N^{*}$ resonances. Excited states of are described as superpositions of particle-hole configurations including $N N^{^{'} - 1}$ and $N^{*} N^{- 1}$ configurations. Configuration mixing is taken into account on the one-loop level by solving the generalized $N^{*} R P A$ Dyson equation. The underlying coupled channels formalism is derived and response functions is discussed. Applications of the approach are illustrated for charge-exchange modes of asymmetric nuclear matter and finite nuclei. The spectral gross structures of corresponding excitations in finite nuclei are investigated in local density approximation. Applications of the approach to resonance studies by high-energy heavy ion reactions are recapitulated.
Comments:
contributed paper to Festschrift for L.D. Roper's 90th birthday
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2601.12043 [pdf]
Acta Phys.Polon.B(2026)·0 citations
03
[Submitted on 18 Jan 2026]
Radiative strength functions from the energy-localized Brink-Axel hypothesis
Oliver C. Gorton · Konstantinos Kravvaris · Jutta E. Escher · Calvin W. Johnson
Radiative strength functions (RSFs) model the bulk electromagnetic response of highly-excited nuclei and are critical inputs for statistical reaction codes. In this paper, we present a definition of the RSF that is consistent with Hauser-Feshbach reaction codes and that can be efficiently computed with the shell model using the Lanczos strength-function (LSF) method. We introduce a variant of the shell model LSF method that exploits the energy-localized Brink-Axel hypothesis, which makes it possible to compute both electric and magnetic RSFs across all energies relevant to capture reactions. We verify agreement with the conventional definition of RSFs with benchmark calculations of $^{24}$ Mg, then present novel results for $^{56}$ Fe. For $^{56}$ Fe we find that: (i) the M1 RSF shape evolves smoothly with excitation energy, consistent with the energy-localized Brinkl-Axel hypothesis, (ii) both M1 and E1 transitions contribute significantly to the radiative strength below the photo-absorption threshold, and (iii) within the sdpf model space, the strength below 3 MeV observed in Oslo-type experiments cannot be fully reproduced. These results pave the way for a coherent microscopic description of the RSFs and further motivate the use of energy-dependent RSFs in modern reaction codes.
Comments:
15 pages, 8 figures, to be submitted to Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.12225 [pdf]
PRC(2026)·2 citations
04
[Submitted on 18 Jan 2026]
Signatures of QCD conductivities in heavy-ion collisions
Akihiko Monnai🇯🇵 · Grégoire Pihan🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸
Dissipative processes are pivotal for understanding the hydrodynamic evolution of hot and dense QCD matter created in relativistic nuclear collisions. The interplay of multiple conserved charges -- net baryon, strangeness, and electric charge -- is of particular interest. We simulate the longitudinal hydrodynamic evolution with the three diffusion currents in a hydrodynamic model with a lattice-QCD-based equation of state, NEOS-4D, and estimate rapidity distributions including diffusive corrections to the phase-space distribution in the presence of multiple charges, which ensure charge conservation at particlization. We determine the response of particle yields at midrapidity to changes in the diagonal and off-diagonal conductivities. Inversely, we find that most components of the conductivity matrix can be constrained experimentally using identified particle multiplicities at different collision energies.
Comments:
16 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2601.12384 [pdf]
PRC(2026)·2 citations
05
[Submitted on 18 Jan 2026]
Revisiting $^{7}$ Be Weak and Radiative Transition Rates in Big Bang Nucleosynthesis: Implications for the Primordial Lithium Problem
Simone Taioli🇮🇹 · Francesca Triggiani🇮🇹 · Stefano Simonucci🇮🇹
The primordial 7Li abundance predicted by standard Big Bang nucleosynthesis (BBN) exceeds observations in old, metal-poor stars by a factor of 3-4. Since most primordial 7Li is produced as 7Be and subsequently converted by electron capture (EC), additional 7Be destruction channels may affect its final abundance. We investigate EC and antineutrino capture (AC), positron decay from the 7Be nuclear excited state, and proton capture (PC), including 7Be(p,gamma)8B, stimulated emission (SE), plasma screening, and a three-body Auger-like channel transferring the capture energy to a continuum electron. Weak rates are calculated from first principles using perturbation theory with explicitly evaluated hadronic and leptonic currents, while thermally averaged nuclear rates are obtained from the relevant cross sections over 10 < kT < 100 keV. The EC rate rapidly decreases as the Universe expands and cools, while AC enhances weak destruction mainly at early times. SE and screening increase the 7Be(p,gamma)8B rate by only 1-3% at kT about 87 keV. The Auger-like cross section is about 4 x 10^-3 of the radiative channel at kT = 100 keV and falls to about 10^-10 at 10 keV. Our first-principles weak rates differ substantially from previous log(ft)-based estimates, yielding a 7Be half-life of about two days under BBN conditions, nearly one order of magnitude different from phenomenological predictions. Nevertheless, EC, PC, and beta+ decay provide only percent-level corrections to the dominant 7Be(n,p)7Li channel and cannot resolve the cosmological lithium problem. These results motivate a first-principles reassessment of the full BBN nuclear network before invoking physics beyond the Standard Model.
Comments:
24 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Computational Physics (physics.comp-ph)
arXiv:
2601.12438 [pdf]
0 citations
06
[Submitted on 18 Jan 2026]
Microscopic investigation of magnetic and antimagnetic rotational motion in atomic nuclei
W. Tawseef · Nazira Nazir · S. Jehangir · J. A. Sheikh · C. Majumder · S. Chakraborty · G. B. Vakil · G. H. Bhat · N. A. Rather
In the present work, we have generalized the projected shell model (PSM) approach to include the quasiparticle excitations from two major oscillator shells, and have also extended the basis space to five-quasiparticle configurations for odd-mass nuclei. The magnetic and antimagnetic rotational structures observed in odd-neutron Pd- and Cd-isotopes have been investigated as a first major application of the new development. It is shown that PSM approach provides a reasonable description of the observed properties of magnetic and antimagnetic rotational bands.
Comments:
15 pages, 17 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.12496 [pdf]
PRC(2026)·0 citations
07
[Submitted on 19 Jan 2026]
Numerical study of the two-boson bound-state problem with and without partial-wave decomposition
Wolfgang Schadow
The validation of numerical methods is a prerequisite for reliable few-body calculations, particularly when moving beyond standard partial-wave decompositions. In this work, we present a precision benchmark for the two-boson bound-state problem, solving it using two complementary formulations: the standard one-dimensional partial-wave Lippmann--Schwinger equation and a two-dimensional formulation based directly on vector variables. While the partial-wave approach is computationally efficient for low-energy bound states, the vector-variable formulation becomes essential for scattering applications at higher energies where the partial-wave expansion converges slowly. We demonstrate the high-precision numerical equivalence of both methods using rank-one separable Yamaguchi potentials and non-separable Malfliet--Tjon interactions. Furthermore, for the Yamaguchi potential, we derive exact analytical expressions quantifying the systematic errors introduced by finite momentum- and coordinate-space cut-offs. These analytical bounds provide a rigorous tool for disentangling discretization errors from truncation effects in few-body codes. The results establish a highly controlled methodological benchmark that provides a detailed baseline for vector-variable algorithms intended for more complex three- and four-body calculations.
Comments:
17 pages, 16 tables, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.13116 [pdf]
Few Body Syst.(2026)·1 citation
08
[Submitted on 19 Jan 2026]
Trace Anomaly of Cold Dense Matter Constrained by Collective Flow
Bao-An Li🇺🇸
The trace anomaly of dense matter, $Δ \equiv 1/3 - P / ε$ , defined through the ratio $w \equiv P / ε$ of pressure $P$ to energy density $ε$ , quantifies deviations from conformal symmetry and provides a dimensionless measure of the stiffness of the equation of state (EOS) relevant for both neutron stars and heavy-ion collisions. While $Δ (ε)$ has recently been inferred from neutron star observations, we report the first Bayesian extraction of the trace anomaly from collective flow observables in intermediate-energy heavy-ion collisions. By employing transport-model simulations that explicitly decouple the cold matter mean-field potential from thermal effects, we directly constrain the EOS of cold dense matter. Remarkably, the trace anomaly inferred from laboratory flow data agrees quantitatively, within $68%$ credible intervals, with independent astrophysical posterior bands. This nontrivial agreement demonstrates that heavy-ion collisions and neutron star observations probe the same macroscopic properties in a mutually consistent way, establishing the dense-matter trace anomaly as a composition-insensitive macroscopic bridge observable across widely different physical environments.
Comments:
Version accepted by Phys. Rev. Lett
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2601.13374 [pdf]
PRL(2026)·8 citations
09
[Submitted on 20 Jan 2026]
Superfluid Band Theory for the Rod Phase in the Magnetized Inner Crust Matter: Entrainment, Spin-orbit Coupling, Spin-triplet Pairing
Kenta Yoshimura · Kazuyuki Sekizawa
The inner crust of neutron stars hosts a rich variety of nuclear phenomena and provides a unique environment for exploring microscopic nuclear properties relevant to diverse astrophysical observations. Particularly magnetars, which possess extremely strong magnetic-fields, have attracted increasing attention in connection with nuclear spin dynamics and unconventional pairing correlations. This work is dedicated to develop a comprehensive theoretical framework to describe the structures and properties of two-dimensional (rod-phase) matter in the neutron star inner crust, incorporating band-structure effects, neutron spin-triplet pairing, and strong magnetic-fields on an equal footing. The main results of this study can be summarized as follows. In the first place, the magnetic-fields of the order of $1 0^{16}$ G are found to substantially enhance the neutron effective mass by a factor of approximately $1.5$ , indicating a significant modification of entrainment properties in strongly magnetized crustal matter. In the second place, while the overall behavior of pairing phase transitions is qualitatively similar to that observed in one-dimensional systems studied previously, the present two-dimensional calculations reveal a nontrivial role of the spin-orbit interaction in inducing spin-polarization under magnetic fields. In the third place, concerning spin-triplet superfluidity, the rank-0 component is shown to emerge as a consequence of magnetic-field-induced spin-polarization, irrespective of the presence of spin-triplet pairing interactions, whereas the rank-2 component appears only when the corresponding interaction channel is included.
Comments:
24 pages, 6 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.13636 [pdf]
4 citations
10
[Submitted on 20 Jan 2026]
Pairing correlations, orientations and quantum fluctuations in one- and two-nucleon transfer reactions at sub-barrier energies
Dandan Zhang · Bo Li · Dario Vretenar · Tamara Nikšić · Pengwei Zhao · Jie Meng
This work investigates one- and two-neutron transfer in the $^{96} Zr +^{40} Ca$ reaction at sub-barrier energies using a microscopic framework based on time-dependent covariant density functional theory (TD-CDFT). Pairing correlations are incorporated via the time-dependent BCS approximation, which is shown to significantly enhance pair transfer, as evidenced by an increased two-neutron transfer probability. The oblate deformation of $^{96}$ Zr causes the transfer probabilities to vary by orders of magnitude with orientation; a direct comparison with experiment is enabled by averaging results over thirteen systematically chosen orientations. While the orientation-averaged one-neutron transfer probabilities agree well with data, the two-neutron channel is suppressed below the Coulomb barrier. This suppression is attributed to missing quantum fluctuations in the semiclassical TD-CDFT approach. To test this, we employ the generalized time-dependent generator coordinate method (TDGCM), which confirms that quantum fluctuations are essential for an accurate description of sub-barrier two-neutron transfer dynamics.
Comments:
8 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2601.13667 [pdf]
PRC(2026)·1 citation
11
[Submitted on 20 Jan 2026]
Comparative study of quartet superfluid state: Quartet Bardeen-Cooper-Schrieffer theory and generalized Nambu-Gor'kov formalism
Yixin Guo · Hiroyuki Tajima · Haozhao Liang
We theoretically investigate a quartet superfluid state in fermionic matter by using the quartet Bardeen-Cooper-Schrieffer (BCS) variational theory and the Green's function method. We demonstrate that the quartet BCS theory with the multiple-infinite-product ansatz successfully reproduces an exact four-body result in a one-dimensional four-component Fermi gas at the dilute limit, in contrast to the single-infinite-product ansatz. To see the validity of the quartet BCS state, we derive the self-consistent equation for the quartet superfluid order parameter within the generalized imaginary-time Nambu-Gor'kov formalism, which is found to be consistent with the quartet BCS variational equation. Moreover, by numerically computing the momentum-resolved single-particle spectral function in a one-dimensional system, we discuss how the single-particle spectra evolve with increasing the strength of the four-body cluster formation. We show that a coherent BCS-like quasiparticle branch on the weak-coupling side evolves into a strongly damped, continuum-dominated spectrum in the strong-coupling side, while nonzero quartet superfluid order parameter persists throughout the crossover regime. Our results would be useful for understanding beyond-BCS pairing effects and four-body cluster formations in fermionic systems in an interdisciplinary way.
Comments:
12 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Superconductivity (cond-mat.supr-con); Atomic Physics (physics.atom-ph)
arXiv:
2601.13825 [pdf]
1 citation
12
[Submitted on 20 Jan 2026]
On the Realization of Quantum State Teleportation in Proton Systems
H. Witala🇵🇱
We discuss how to generate entangled Bell states of two nucleons using unpolarized nucleon-nucleon scattering or the exclusive deuteron breakup reaction. We follow the the approach of Z. X. Shen et al., arXiv:2510.24325v1 [nucl-th], where Bell states were identified in unpolarized proton-proton elastic scattering. We confirm these results and show that, in the unpolarized proton-deuteron breakup reaction, it is also possible to generate proton-proton entangled Bell states in kinematically complete proton-proton quasi-free scattering (QFS) and final-state interaction (FSI) configurations. We also discuss an experimental setup that, by exploiting such entangled states, could enable the teleportation of quantum mechanical states in a three-proton system. Such an experiment requires triple coincidences among the outgoing nucleons, which precludes the use of entangled Bell states generated with extremely polarized incoming particles. Since counting rates for unpolarized reactions are much higher than for polarized ones, the present results open a pathway toward searching for signatures of quantum state teleportation in hadronic systems.
Comments:
51 pages, 36 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.14145 [pdf]
PRC(2026)·1 citation
13
[Submitted on 20 Jan 2026]
Influence of Finite-Nuclei Constraints on High-Density Transitions and Neutron Star Properties
Anagh Venneti · Sarmistha Banik · Bijay K Agrawal
We construct posterior distributions of the equation of state (EoS) for matter beyond the inner crust of neutron stars by incorporating finite nuclei (FN) constraints within relativistic mean field models. These constraints are implemented in three complementary ways: (i) through theoretical bounds on the EoS, (ii) implicitly via nuclear matter parameters, and (iii) explicitly by enforcing consistency with experimental binding energies and charge radii of selected nuclei. The resulting low-density nucleonic EoSs are subsequently matched to a model-agnostic speed-of-sound parametrization, constrained by astrophysical observations, including NICER mass-radius measurements, tidal deformability limits from GW170817, and lower bounds on the maximum neutron-star mass inferred from radio pulsar observations. We find that the admissible range of the transition density is strongly sensitive to the choice of the low-density EoS. In particular, the inclusion of explicit FN constraints significantly reduces the allowed parameter space of the nucleonic EoS at low densities, narrowing the transition-density range by nearly a factor of two. Consequently, neutron-star properties inferred from EoSs with explicit FN constraints differ substantially, with especially pronounced effects for low-mass neutron stars and their correlations with nuclear matter parameters. A quantitative comparison, using metrics based on Mahalanobis distance, shows consistency of the explicit constraints with PSRs J0740+6620, J0030+0451, and J0437-4715, but suggest a possible tension with PSR J0614-3329. These findings underscore the critical importance of a consistent treatment of finite-nuclei properties for reliably inferring the behavior of high-density matter and the presence of possible phase transitions from astrophysical observations.
Comments:
16 Pages, 7 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2601.14194 [pdf]
2 citations
14
[Submitted on 16 Jan 2026] (cross-list from math-ph)
Existence of Decreasing Nambu Solutions to the Rainbow Ladder Gap Equation of QCD by Cone Compression
Alex Roberts
Studying Nambu solutions of the rainbow-ladder gap equation in QCD at zero temperature and chemical potential, we prove that the mass function emerges continuously from zero as the interaction strength is increased past the critical point for all positive, asymptotically perturbative kernels almost everywhere continuous in $L^{1}$ using the Krasnosel'skii-Guo Cone Compression Theorem. We prove that the coupled system of equations must have a positive, continuous Nambu solution with decreasing mass function for all current quark masses for a class of models which includes the physical point of a popular model of QCD by using a hybrid Krasnosel'skii-Schauder Fixed Point Theorem.
Subjects:
Mathematical Physics (math-ph); math.FA (math.FA); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2601.11752 [pdf]
0 citations
15
[Submitted on 16 Jan 2026] (cross-list from hep-ph)
Minkowski Space Dynamics and Light-Front Projection
Wayne de Paula🇧🇷 · Tobias Frederico🇧🇷
We explore the connection between the four-dimensional Minkowski-space Bethe-Salpeter equation and its light-front projection, emphasizing the implications for bound-state dynamics. Our approach incorporates dressed particles, such as quarks, via the integral representation of the corresponding propagator. We analyze the light-front dynamics of the valence component of the physical state using a hierarchical set of Green's functions, which reveals its coupling to higher Fock components when dressed particles are considered. We also present the light-front Faddeev-Bethe-Salpeter equations for three-body systems with dressed constituents. Furthermore, we discuss formal developments that are central to connecting the three-dimensional light-front dynamics onto the null-plane and the four-dimensional Minkowski-space framework, based on the Nakanishi integral representation. Selected applications to hadron structure are also reviewed.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2601.11760 [pdf]
Eur.Phys.J.ST(2026)·2 citations
16
[Submitted on 17 Jan 2026] (cross-list from hep-lat)
Asymptotic Long-Distance Expansion of Euclidean Correlators in Lattice Parton Applications
Xiangdong Ji🇨🇳 · Yizhuang Liu🇵🇱 · Yushan Su🇺🇸
Bilinear Euclidean quark and gluon correlators with Wilson links have been used widely for applications of large-momentum effective field theories to computing non-perturbative collinear and soft parton physics. Due to color confinement, these correlators decay exponentially at large spatial distances, a behavior crucial for computing momentum-space Fourier transformations with controlled errors from lattice QCD data. Using heavy-quark effective theory reduction, dispersive analysis, Lorentz symmetry, and heavy-flavor spectra, we determine the leading and next-to-leading asymptotic behaviors and relate the expansion parameters to binding energies of heavy-flavor hadrons. We demonstrate the results through two-loop calculations in $ϕ^{3}$ theory and from the perspective of locality and analyticity. We also study the impact of the asymptotic analysis on realistic lattice QCD data and demonstrate reliable error estimates.
Comments:
93 pages, 32 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2601.12189 [pdf]
14 citations
17
[Submitted on 18 Jan 2026] (cross-list from hep-ph)
Open charm production and $Λ_{c}^{+} / D^{0}$ ratio in pp and Au+Au collisions at the RHIC
Bijun Fan🇨🇳 · Chao Zhang🇨🇳 · Liang Zheng🇨🇳 · Shusu Shi🇨🇳
We study open charm hadrons production in pp and Au+Au collisions at $s_{NN} = 200$ ~GeV using an improved a multi-phase transport (AMPT) model. Specifically, we show the transverse-momentum spectra and nuclear modification factors $R_{AA}$ of $D^{0}$ mesons and $Λ_{c}^{+}$ baryons, as well as the $Λ_{c}^{+} / D^{0}$ ratio in pp and Au+Au collisions. The results obtained from the AMPT model simulations are compared with the STAR experimental data and found to be consistent. We further investigate the $Λ_{c}^{+} / D^{0}$ ratio by evaluating contributions from coalescence, fragmentation, and the combined coalescence+fragmentation mechanisms, and we find that fragmentation alone underestimates the pronounced enhancement in Au+Au relative to pp at low and intermediate $p_{T}$ , whereas the coalescence+fragmentation mechanism reproduces the observed trend significantly better. These results indicate that coalescence plays a key role in charm baryon productions and helps constrain the relative importance of different hadronization mechanisms in the ultra-relativistic nuclear collisions.
Comments:
9 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.12287 [pdf]
PRC(2026)·1 citation
18
[Submitted on 18 Jan 2026] (cross-list from nucl-ex)
Impact of the $^{5}$ Li resonance in $α$ - $p$ elastic scattering on precision measurements of neutrino oscillation parameters
Mingyuan Wang🇨🇳 · Yiyang Li🇨🇳 · Suqing Hou🇨🇳 · Fei Xiao🇨🇳 · Yaoguang Wang🇨🇳 · Zeyuan Yu🇨🇳
Precision measurements of four neutrino oscillation parameters, $θ_{12}$ , $θ_{13}$ , $Δ m_{21}^{2}$ , and | $Δ m_{31}^{2}$ |, face significant interference from a previously overlooked correlated background. Recent findings from the SNO+ and JUNO experiments reveal that cascade decays of $^{214}$ Bi- $^{214}$ Po in liquid scintillator detectors can mimic inverse beta decay signals from reactor and geoneutrinos, with a misidentification probability on the order of $1 0^{- 4}$ when hydrogen neutron capture is used, a rate ten times higher than Geant4 simulations predicted. This work identifies the $^{5}$ Li resonance in $α$ - $p$ elastic scattering as the underlying cause. For alpha energies above 5~MeV, the cross section is hundreds of times larger than that of Rutherford scattering. After correctly incorporating the differential cross section into Geant4, the misidentification probability is recalculated as 1.9 $\times$ 10 $^{- 4}$ . The simulated shape of the long tail in the alpha deposited energy also differs from the extrapolation models currently used by SNO+ and JUNO. These results will assist both experiments in more accurately estimating this novel background, thereby refining measurements of neutrino oscillation parameters and the geoneutrino flux. Additionally, the study implies an overlooked background with a rate of 0.5 events per detector per day in the Daya Bay $θ_{13}$ analysis using hydrogen neutron capture, leading to an increase of $sin^{2} 2 θ_{13}$ by approximately 0.012. Consequently, the Particle Data Group's reported $sin^{2} θ_{13}$ value shall increase by about 0.006~(1 $σ$ ).
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2601.12452 [pdf]
0 citations
19
[Submitted on 19 Jan 2026] (cross-list from hep-ph)
QCD-Like Theories with Different Color Numbers
Toru Kojo🇯🇵
Quantum chromodynamics (QCD) with a general number of colors, $\Nc$ , provides a powerful theoretical laboratory to explore the dynamics of non-Abelian gauge theories. Although $\Nc = 3$ does not look a large number, the $1/ \Nc$ expansion provides us with a very useful classification and book-keeping scheme for hadronic processes and sharpens conceptions otherwise obscured in real-world QCD with $\Nc = 3$ . Important applications are dense QCD matter where the first principle methods for QCD are not available and many conceptual issues remain to be clarified. In this chapter we first review hadrons at large $\Nc$ from the viewpoint of quark-gluon dynamics, and then extend the discussions to hot/dense matter, focusing on confinement-deconfinement aspects. We emphasize how the large- $\Nc$ limit provides a unified organizing principle for hadronic and quark degrees of freedom in regimes where first-principle methods are limited. Two-color and isospin QCD, for which lattice simulations at finite density can be performed for a special reason, is reviewed.
Comments:
15 pages, 8 figures, a contribution to the Encyclopedia of Nuclear Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.12650 [pdf]
0 citations
20
[Submitted on 19 Jan 2026] (cross-list from hep-ph)
Investigation of deuteron-like singly bottomed dibaryon resonances
Yuxuan Du🇨🇳 · Yanyue Pan🇨🇳 · Xinmei Zhu🇨🇳 · Zhiyun Tan🇨🇳 · Hongxia Huang🇨🇳 · Jialun Ping🇨🇳
We perform a systematical investigation of the existence of the deuteron-like singly bottomed dibaryon resonance states with strangeness $S = - 1, - 3, - 5$ in the chiral quark model. Two resonance states with strangeness $S = - 1$ are obtained in the baryon-baryon scattering process. The first candidate is $Σ Σ_{b}$ in the $Λ Λ_{b}$ and $N Ξ_{b}^{*}$ scattering process, with the resonance energy 6974.22 MeV - 6975.37 MeV and the decay width 14.450 MeV, respectively; the other one is $Σ Σ_{b}^{*}$ in the $N Ξ_{b}$ and $N Ξ_{b}^{'}$ scattering process, with the resonance energy 6990.69 MeV - 7008.37 MeV and the decay width 43.790 MeV, respectively. The Root Mean Square (RMS) radius calculation shows that the former tends to be in a compact structure, while the latter tends to be in a molecular structure. Both of these resonance states are worthy of experimental exploration. Furthermore, it should be emphasized that the effect of channel-coupling is of great importance in exploring exotic hadron states, and investigating the scattering process may serve as an effective approach to identifying genuine resonances.
Comments:
17 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2601.12670 [pdf]
PRD(2026)·0 citations
21
[Submitted on 19 Jan 2026] (cross-list from nucl-ex)
Electric dipole strength in $s d$ -shell nuclei from small-angle proton scattering
R.W. Fearick (1)🇿🇦 · O. Le Noan (2,3)🇫🇷 · H. Matsubara (4,5)🇯🇵 · P. von Neumann-Cosel (6)🇩🇪 · K. Sieja (2,3)🇫🇷 · A. Tamii (4) ((1) Department of Physics, University of Cape Town, Rondebosch 7700, South Africa, (2) Universite de Strasbourg, IPHC, 23 rue du Loess, 67037 Strasbourg, France, (3) CNRS, UMR7178, 67637 Strasbourg, France, (4) Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan (5) School of Medical Sciences, Fujita Health University, Aichi 470-1192, Japan, (6) Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany)🇯🇵
The present work reports new total photoabsorption cross sections for the $N = Z$ nuclei in the $s d$ -shell $^{20}$ Ne, $^{24}$ Mg, $^{28}$ Si, $^{32}$ S, $^{36}$ Ar, and for $^{26}$ Mg. The results are compared to predictions of a data-driven artificial neural network application and to configuration-interaction shell-model calculations covering the excitation energy region of the isovector giant dipole resonance. Double-differential cross sections of the $(p, p^{'})$ reaction at 295 MeV have been measured between $0^{\circ}$ and $1 4^{\circ}$ . The angular distributions of the $E 1$ parts due to Coulomb excitation have been extracted with a multipole decomposition analysis for excitation energies 12 to 24 MeV and converted to equivalent photoabsorption cross sections with the virtual photon method. Reasonable agreement of the photoabsorption cross sections with previous experiments is found for $^{24}$ Mg and $^{28}$ Si, while the present results diverge for $^{32}$ S. For the first time, data are presented for $^{20}$ Ne, $^{26}$ Mg and $^{36}$ Ar. Configuration-interaction shell-model calculations provide an overall satisfactory description of the fragmented $E 1$ strength distributions. The same holds for absolute cross sections except for $^{26}$ Mg and $^{36}$ Ar, where the experimental results significantly exceed the expected exhaustion of the Thomas-Reiche-Kuhn energy-weighted sum rule. Fot light nuclei, there is a larger model dependence compared to previous analyses in heavy nuclei, in particular for excitation energies above 20 MeV, due to the need to constrain the continuum background with additional assumptions. The overall success of the shell-model approach to describe the features of the experimental photoabsorption cross sections motivates its application in large-scale reaction network calculations aiming at an understanding of the mass composition of ultrahigh-energy cosmic rays.
Comments:
10 pages, 6 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2601.12829 [pdf]
PRC(2026)·0 citations
22
[Submitted on 19 Jan 2026] (cross-list from hep-lat)
Lattice-QCD validation of hadron mass and trace-anomaly decomposition sum rules
Dennis Bollweg🇺🇸 · Heng-Tong Ding🇨🇳 · Xiang Gao🇺🇸 · Ran Luo🇨🇳 · Swagato Mukherjee🇺🇸
We present the first lattice-QCD validation of multiple sum rules associated with quark-gluon decomposition of hadron mass by computing all components from first principles. We achieve this through nonperturbative renormalization of the QCD energy-momentum tensor, including its trace, in a gradient-flow scheme, followed by continuum extrapolations, two-loop matching to the $MS$ scheme, and zero-flow-time extrapolations. These ingredients enable a direct and simultaneous verification, in a common renormalization scheme and scale, of multiple energy-density-based and trace-based mass decomposition sum rules proposed in the literature. We demonstrate the framework for the $η_{c}$ and $J / ψ$ charmonia using three fine lattice spacings with a physical strange-quark and near-physical up- and down-quark masses. We present the first lattice-QCD results for the gravitational form factor $C ˉ$ . We find sizable gluonic contributions to charmonia masses at the hadronic scale, $\sim 15%$ in the Lorcé and Metz-Pasquini-Rodini decompositions. The trace-anomaly contribution in the Ji sum rule is $\sim 6%$ , while the gluonic component of the trace anomaly in the Hatta-Rajan-Tanaka sum rule is $\sim 35%$ . The method is general and can be straightforwardly adopted for lattice-QCD calculations of mass and spin decompositions as well as gravitational form factors of other hadrons and nuclei.
Comments:
22 pages, 15 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.13070 [pdf]
PRL(2026)·2 citations
23
[Submitted on 19 Jan 2026] (cross-list from hep-ph)
Heavy Quarks in the initial stages of Proton-Ion Collisions
Gabriele Parisi🇮🇹
Collisions among heavy ions, like Pb or Au, are a great tool to study the theory of strong interactions, that is Quantum Chromodynamics (QCD). In particular, these experiments are able to give insights on all the complex phases of matter that the theory of QCD allows. In this PhD Thesis we have investigated the initial stages of proton-ion collisions: in particular, we will focus on the first $\sim 0.4$ fm/c ( $\sim 1 0^{- 24}$ s) after the collision, which are dominated by very intense gluon fields, in a state called glasma. We investigated the effect of such fields on the dynamics of heavy quarks (charm and beauty) which are created and evolve in this medium. The effect of the initial gluon fields on heavy quarks is quite substantial, in particular we observe that the glasma provokes a $50%$ dissociation rate on quark-antiquark pairs. Moreover, glasma fields have a large momentum anisotropy, and transmit a large part of such anisotropy to the heavy quarks which evolve in this medium. Finally, we have generalized our study to a non-boost invariant medium, and shown that fluctuations in rapidity do not lead to significant isotropization within glasma timescales.
Comments:
PhD thesis submitted on November 30th, 2025. Largely based on arXiv:2412.07967, arXiv:2505.08441 and (preliminary results of) arXiv:2601.11123
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2601.13076 [pdf]
0 citations
24
[Submitted on 19 Jan 2026] (cross-list from hep-ph)
Bottom-up approach to describe groomed jet data in heavy-ion collisions
Liliana Apolinário🇵🇹 · Diogo Costa🇪🇸 · Alba Soto-Ontoso🇪🇸
The theoretical interpretation of jet observables in heavy-ion collisions is a complex task due to the intricate interplay of perturbative and non-perturbative effects. One way to reduce this complexity is to groom away soft, wide-angle radiation so that perturbative dynamics dominates. Even in this simplified scenario, there are competing explanations for the physical origin of the measured medium-induced modifications. In this paper, we present a minimal approach to compute groomed substructure observables. The core idea is to treat medium effects as an effective energy shift of the hard, vacuum-like substructure. This energy shift includes a gradual onset of colour decoherence effects and thus depends on the jet substructure itself. We first study a NLO-exact dijet configuration in vacuum and apply radiative energy-loss to the two subjets. We find that this minimal setup already captures the narrowing trend of groomed observables but it's not able to quantitatively describe the existing data. Next, we match the NLO matrix-element to a leading-logarithm accurate parton shower and perform a clustering algorithm to recover a two-prong system to which we again apply the energy-loss distribution. Despite its simplicity, the model results in a very good theory-to-data agreement (within $10%$ ) for a broad range of observables including both ALICE and ATLAS kinematics. We also examine the discriminating power of groomed jet data in terms of colour decoherence effects and find that substructure-dependent energy loss yields an overall better agreement.
Comments:
17 pages, 6 figures, 2 appendices
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2601.13310 [pdf]
EPJC(2026)·7 citations
25
[Submitted on 19 Jan 2026] (cross-list from cs.LG)
Quantum Qualifiers for Neural Network Model Selection in Hadronic Physics
Brandon B. Le · D. Keller
As quantum machine-learning architectures mature, a central challenge is no longer their construction, but identifying the regimes in which they offer practical advantages over classical approaches. In this work, we introduce a framework for addressing this question in data-driven hadronic physics problems by developing diagnostic tools - centered on a quantitative quantum qualifier - that guide model selection between classical and quantum deep neural networks based on intrinsic properties of the data. Using controlled classification and regression studies, we show how relative model performance follows systematic trends in complexity, noise, and dimensionality, and how these trends can be distilled into a predictive criterion. We then demonstrate the utility of this approach through an application to Compton form factor extraction from deeply virtual Compton scattering, where the quantum qualifier identifies kinematic regimes favorable to quantum models. Together, these results establish a principled framework for deploying quantum machine-learning tools in precision hadronic physics.
Comments:
12 pages, 5 figures. Proceedings for the 26th International Symposium on Spin Physics (SPIN2025), September 21-26, 2025; Qingdao, Shandong, China
Subjects:
Machine Learning (cs.LG); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2601.13463 [pdf]
1 citation
26
[Submitted on 20 Jan 2026] (cross-list from hep-ph)
Non-perturbative flavor asymmetry in the nucleon and deuteron: The light-front Hamiltonian effective field theory approach
Xianghui Cao🇨🇳 · Shan Cheng🇨🇳 · Yihan Duan🇨🇳 · Yang Li🇨🇳 · Siqi Xu🇨🇳 · Xingbo Zhao🇨🇳
We investigate non-perturbative multi-pion contributions to nucleon flavor asymmetry within the framework of Light-Front Hamiltonian Effective Field Theory (LFHEFT). Utilizing a Fock sector expansion, we systematically incorporate pionic degrees of freedom, with the nucleon-pion interactions governed by a scalar variant of chiral effective field theory. Our results demonstrate that the non-perturbatively calculated longitudinal momentum distributions exhibit significant deviations from leading-order perturbative predictions, emphasizing the importance of higher-order Fock components in describing the proton's sea quark structure. Furthermore, we demonstrate the feasibility of extending this framework to investigate nuclear effects in light nuclei, such as the deuteron. This unified approach provides a consistent basis for analyzing the interplay between intrinsic nucleon structure and nuclear modifications, potentially offering new insights into the flavor asymmetry observed in fixed-target and collider experiments.
Comments:
6 pages, 3 figures, proceeding of the 2025 International Conference on the Structure of Baryons
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.13567 [pdf]
J.Subatomic Part.Cosmol.(2026)·0 citations
27
[Submitted on 20 Jan 2026] (cross-list from hep-ph)
Structure of Bound States with Coulomb plus Short-range Interaction
Chisato Uno🇯🇵 · Tetsuo Hyodo🇯🇵
We study the structure of bound states appearing in systems governed by the Coulomb and short-range interactions. We analyze the binding energies and wave functions of the bound states generated by the Coulomb plus short-range potential. We demonstrate that Coulomb-induced shifts of the binding energy are closely correlated with the spatial distribution of the wave function. Furthermore, we show that the asymptotic behavior of wave functions of weakly bound states is qualitatively altered by Coulomb repulsion, leading to a modification of the near-threshold mass scaling that is otherwise universal for short-range interactions.
Comments:
6 pages, 3 figures, Talk given at The 15th International Conference on Hypernuclear and Strange Particle Physics (HYP2025), Sep. 29 - Oct. 3, 2025, Tokyo, Japan
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.13733 [pdf]
0 citations
28
[Submitted on 20 Jan 2026] (cross-list from hep-ph)
$γ Z$ Box at Low Energy
Balma Duch🇪🇸 · Pere Masjuan🇪🇸 · Hubert Spiesberger🇩🇪
We calculate the 1-loop $γ Z$ box-graph correction to electron-quark scattering at low energy and low momentum transfer. Both electron and quark masses are kept non-zero. From our result, we extract coupling constants for the low-energy effective Lagrangian with parity-violating 4-fermion interaction terms. We study the zero-mass limits and show that a non-zero electron mass is sufficient to obtain finite, well-defined couplings which are insensitive to a hadronic mass cutoff. We finally discuss the impact of our results on the determination of the weak charge of the proton from polarized electron-proton scattering.
Comments:
26 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2601.13819 [pdf]
1 citation
29
[Submitted on 20 Jan 2026] (cross-list from astro-ph.HE)
Rotational enhancement and stability of protoquark stars during thermal evolution
Adamu Issifu🇧🇷 · Andreas Konstantinou🇨🇾 · Prashant Thakur🇰🇷 · Tobias Frederico🇧🇷
We present the first systematic study of rigidly rotating protoquark stars based on isentropic equations of state (EOS) within the density-dependent quark mass (DDQM) framework. Using a quasi-static equilibrium approach, we follow the Kelvin--Helmholtz evolution from hot, lepton-rich matter to a cold, catalyzed quark star (QS). Rotation substantially enhances the maximum stable mass (by up to $\sim 40%$ ), equatorial radius, and key rotational observables, with the ratio of rotational kinetic to gravitational potential energy, $T_{kin} /∣ W ∣$ , reaching $0.18$ -- $0.19$ near the Keplerian limit, indicating a heightened susceptibility to gravitational-wave--emitting instabilities. Thermal evolution introduces a clear ordering: all stellar properties peak during the lepton-rich stages and decrease monotonically as the star cools. Compared to hadronic stars, rotating proto-QSs exhibit larger radii, higher moments of inertia, and stronger quadrupolar deformation, producing a distinct signature in the mass--radius--spin plane. The EOS parameters are constrained using current astrophysical observations, including mass--radius measurements from HESS~J1731--347 and PSR~J0030+0451, the high-mass constraint from PSR~J0740+6620, and mass-radius constraints inferred from GW170817. The results demonstrate that future multimessenger observations must account for both thermal history and rotation to identify quark matter (QM) in compact stars robustly.
Comments:
14 pages, 2 tables, and 8 figures (the version accepted for publication in Physical Review D)
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.13941 [pdf]
PRD(2026)·0 citations
30
[Submitted on 20 Jan 2026] (cross-list from hep-ph)
Frame Dependence in Generalized Chiral Kinetic Theory
Shu-Xiang Ma🇨🇳 · Jian-Hua Gao🇨🇳
We investigate the frame dependence of distribution functions within the framework of generalized chiral kinetic theory. Based on the derived transformation rules governing the choice of frame, we analytically obtain the global equilibrium solution in the presence of vorticity and electromagnetic fields. Our results show that, under the assumption of a varying electromagnetic field, these equilibrium solutions can be uniquely determined.
Comments:
11 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2601.14010 [pdf]
CPC(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE