Nuclear Theory·nucl-th

Wednesday·September 3, 2025

38 papers—18 primary·20 cross-listed

19
Investigating nuclear effects in lepton-ion DIS at the LHC
Reinaldo Francener🇧🇷 · Victor P. Goncalves🇧🇷 · Diego R. Gratieri🇧🇷
Recent studies have demonstrated that the far-forward physics program of the Large Hadron Collider (LHC) can be useful to probe the hadron structure with GeV-TeV neutrinos and muons. In particular, these studies indicate that the measurement of the muon-ion and neutrino-ion cross-sections by the same experiment is feasible. In this paper, we investigate the impact of nuclear effects on the muon-tungsten ( $μ W$ ) and neutrino-tungsten ( $ν W$ ) deep inelastic scattering (DIS) events at FASER $ν$ and its proposed upgrade FASER $ν 2$ . We estimate the rates associated with the inclusive cross-sections and for events with a charm tagged in the final state considering different parameterizations for the nuclear parton distribution functions. These results point out that muon and neutrino-induced interactions probe complementary kinematical ranges and that a simultaneous analysis of associated events will allow to test the universality (or not) of the nuclear effects. Moreover, we propose the study of the ratio between the charm tagged and inclusive events in order to discriminate between the distinct modeling of the nuclear effects at small- $x$ . Our results indicate that a future experimental reconstruction of $μ W$ and $ν W$ DIS events at the LHC is a promising way to improve our understanding of nuclear effects and decrease the current uncertainties in parton distribution functions.
↳ hep-phhep-exnucl-thJHEP(2026)·4 citations
20
Improving the Precision of First-Principles Calculation of Parton Physics from Lattice QCD
Yong Zhao🇺🇸
Large Momentum Effective Theory (LaMET) provides a general framework for computing the multi-dimensional partonic structure of the proton from first principles using lattice quantum chromodynamics (QCD). In this effective field theory approach, LaMET predicts parton distributions through a power expansion and perturbative matching of a class of Euclidean observables -- quasi-distributions -- evaluated at large proton momenta. Recent advances in lattice renormalization, such as the hybrid scheme with leading-renormalon resummation, together with improved matching kernel that incorporates higher-loop corrections and resummations, have enhanced both the perturbative and power accuracy of LaMET, enabling a reliable quantification of theoretical uncertainties. Moreover, the Coulomb-gauge correlator approach further simplifies lattice analyses and improves the precision of transverse-momentum-dependent structures, particularly in the non-perturbative region. State-of-the-art LaMET calculations have already yielded certain parton observables with important phenomenological impact. In addition, the recently proposed kinematically enhanced lattice interpolation operators promise access to unprecedented proton momenta with greatly improved signal-to-noise ratios, which will extend the range of LaMET prediction and further suppress the power corrections. The remaining challenges, such as controlling excited-state contamination in lattice matrix elements and extracting gluonic distributions, are expected to benefit from emerging lattice techniques for ground-state isolation and noise reduction. Thus, lattice QCD studies of parton physics have entered an exciting stage of precision control and systematic improvement, which will have a broader impact for nuclear and particle experiments.
↳ hep-lathep-phhep-thnucl-thResearch(2026)·5 citations
21
Nonradial oscillations of stratified neutron stars with solid crusts: Mode characterization and tidal resonances in coalescing binaries
Yong Gao · Hao-Jui Kuan · Cheng-Jun Xia · Hector O. Silva · Masaru Shibata
Dynamical tides of neutron stars in the late stages of binary inspirals provide a viable probe into dense matter through gravitational waves, and potentially trigger electromagnetic precursors. We model the tidal response as a set of driven harmonic oscillators, where the natural frequencies are given by the quasinormal modes of a nonrotating neutron star. These modes are calculated in general relativity by applying linear perturbation theory to stellar models that include a solid crust and compositional stratification. For the mode spectrum, we find that the canonical interface mode associated with the crust-core boundary vanishes in stratified neutron stars and is replaced by compositional gravity modes with mixed gravity-interfacial character, driven primarily by strong buoyancy in the outer core. We also find that fluid modes such as the core gravity mode and the fundamental mode can penetrate the crust, and we establish a criterion for such penetration. Regarding the tidal interaction, we find that transfer of binding energy to oscillations is dominated by the fundamental mode despite its frequency being too high to resonate with the tidal forcing. In general, we find that lower-frequency modes induce gravitational-wave phase shifts smaller than $\sim 1 0^{- 3}, rad$ for the equation of state we consider. We discover that nonresonant fundamental and crustal shear modes can trigger crust breaking already near the first gravity-mode resonance, while gravity-mode resonance concentrates strain at the base of the crust and may marginally crack it. These results suggest that both resonant and nonresonant excitations can overstress the crust and may channel energy into the magnetosphere prior to merger, potentially powering electromagnetic precursors. Our work represents an important step toward realistic modeling of dynamical tides of neutron stars in multimessenger observations.
↳ astro-ph.HEgr-qchep-phnucl-thPRD(2025)·12 citations
22
Theory overview: electroweak emission from heavy-ion collisions
Greg Jackson🇫🇷
An important class of observables in the heavy-ion collision programme concerns probes which are not sensitive to the prevailing strong interactions of QCD. The emission of photons, weak gauge bosons, and leptons fall into this category. Here I will describe the current status of such investigations, focusing on the emerging theoretical picture and its uncertainties.
↳ hep-phhep-latnucl-thEPJ Web Conf.(2026)·3 citations
23
Multi-messengers from the radioactive decay of $r$ -process nuclei
Axel Gross · Samuel Cupp · Matthew R. Mumpower
The radioactive $β$ -decay of nuclei synthesized in the rapid neutron capture process ( $r$ -process) releases a variety of particles, including electrons, $γ$ -rays, neutrinos, and neutrons. These particles provide a rich set of multimessenger signals that carry information about the astrophysical environments where neutron-rich nucleosynthesis occurs. In this work, we calculate from first principles the emission spectra resulting from the $β$ -decay of $r$ -process nuclei. Our approach incorporates detailed nuclear structure and decay data to model the energy distributions of each particle species. We couple the spectra with a nuclear reaction network simulation to obtain the temporal evolution of these distributions. We find that the emission distributions vary significantly in time and are non-thermal, with substantial average energies. We investigate these nuclear signals as a direct probe of heavy element formation and show that they are complementary observables to kilonova.
↳ astro-ph.HEastro-ph.SRnucl-thApJL(2025)·3 citations
24
Machine learning driven identification of heavy flavor decay leptons in proton-proton collisions at the Large Hadron Collider
Raghunath Sahoo🇮🇳 · Kangkan Goswami🇮🇳 · Suraj Prasad🇮🇳
The study of heavy-flavor hadrons is topical in the era of precision measurements, which is useful to test theories based on pQCD. The heavy-flavor hadrons are produced initially during heavy-ion or hadronic collisions and are one of the best probes to understand the initial stages of the collisions as well as the system evolution. In experiments, the heavy-flavor sectors are studied directly via their decay to different hadrons or di-leptons or via their semi-leptonic decay, which is accompanied by additional neutrinos. However, their measurement in experiments is resource-intensive and requires input from different Monte-Carlo event generators. In this study, we provide an independent method based on Machine Learning algorithms to separate such leptons coming from heavy-flavor semi-leptonic decays. We use PYTHIA8 to generate events for this study, which gives a good qualitative and quantitative description of heavy-flavor production in $pp$ collisions. We use the XGBoost model for this study, which is trained with $pp$ collisions at $s = 13.6$ ~TeV. We use \DCAXY, \DCAZ~and pseudo-rapidity as the input to the machine. The ML model provides an accuracy of 98\% for heavy-flavor decay electrons and almost 100\% for heavy-flavor decay muons.
↳ hep-phhep-exhep-thnucl-thPRD(2026)·3 citations
25
$S$ -wave kaon-nucleon interactions from lattice QCD at the physical point
Kotaro Murakami🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Yan Lyu🇯🇵 · Wren Yamada🇯🇵
We investigate S-wave kaon-nucleon ( $K N$ ) interactions with strangeness $S = + 1$ in lattice QCD using the time-dependent HAL QCD method. Employing the $(2 + 1)$ -flavor gauge configuration with $m_{π} \approx 137 MeV$ and $m_{K} \approx 502 MeV$ , we calculate the $K N$ potentials at the leading order in the derivative expansion. The potentials in both isospin channels ( $I = 1$ and $I = 0$ ) exhibit repulsion at short distances, while only the $I = 0$ potential has a small attractive pocket at intermediate distances. From these potentials, we compute the phase shifts as well as the low-energy scattering parameters. The obtained phase shifts show no signals corresponding to resonances or bound states in both isospin channels, suggesting the absence of the $Θ^{+} (1540)$ pentaquark in the S-wave $K N$ systems. The results for $I = 0$ suggest that the scattering amplitudes in this channel are dominated by P-wave components rather than S-wave.
↳ hep-lathep-phnucl-exnucl-thPRD(2026)·4 citations
26
Non-diagonal DVCS and studies of hadronic structure with $N \to N^{*}$ transition GPDs
Kirill Semenov-Tian-Shansky
Transition generalized parton distributions (GPDs) describe matrix elements of nonlocal partonic QCD operators between the ground and excited baryon states and provide new tools for quantifying and interpreting the structure of baryon resonances in QCD. We discuss a description of non-diagonal Deeply Virtual Compton Scattering process involving a transition between a nucleon and a nucleon resonance in the $π N$ system within the framework of transition GPDs. We address the physical content of $N \to N^{*}$ and $N \to Δ$ transition GPDs, review the existing theoretical models and present theoretical estimates of related observables for the kinematic conditions corresponding to the experimental studies with JLab@12GeV. We also discuss the perspective of exploring resonance production with help of transition GPDs and consider the application of the Froissart-Gribov projections to study excitation of nucleon resonances by means of QCD probes with spin- $J$ .
↳ hep-phhep-exnucl-thPoS(2026)·0 citations
27
$w$ -mode oscillation of neutron star in a new relativistic hybrid model
D. Dey🇮🇳 · Jeet Amrit Pattnaik🇮🇳 · R. N. Panda🇮🇳 · S. K. Patra🇮🇳
We investigate how the pulsation frequencies of axial gravitational-wave modes ( $w$ -modes) in a non-rotating neutron star depend on its composition, particularly when including quarkyonic matter and fermionic dark matter. These modes emerge from the coupling between the star's fluid component and the gravitational field of general relativity, which are highly damped and characterized by complex frequencies with comparable real and imaginary parts. Using a relativistic mean field formalism for the nucleonic component, we modeled the neutron star's interior, while the exterior is analyzed through the complex-coordinate method to determine the $w$ -modes. Our study employs a realistic equation of state, based on different physical assumptions and covering a broad area of observational constraints, starting from finite nuclei to nuclear matter with extreme conditions. The numerical findings demonstrate that axial $w$ -modes provide valuable insights into the properties of neutron star matter, highlighting their significance in probing the star's internal structure.
↳ astro-ph.HEhep-thnucl-thNPB(2026)·1 citation
28
Composite nature of exotic states from data analysis
Xian-Wei Kang
We introduce two basic concepts: the compositeness for resonance and the Castillejo-Dalitz-Dyson (CDD) pole. Applying them to hadron states $X (3872)$ , $Z_{b} (10610)$ and $Z_{b} (10650)$ , and $T_{cc}$ , we obtain their compositeness values and achieve deeper insights into their inner structure.
↳ hep-phhep-exnucl-thPoS(2026)·0 citations
29
Hadronic vacuum polarization effect in muonic atoms
Zoia A. Mandrykina🇩🇪 · Moritz Thierfeld🇩🇪 · Natalia S. Oreshkina🇩🇪
The hadronic vacuum polarization (HVP) corrections to energy levels in muonic atoms are studied systematically across the periodic table. Two nuclear charge distribution models have been considered, with partly analytical solution for an homogeneously charged sphere model and direct numerical integration for a Fermi nuclear charge distribution. Our comparison reveals a good agreement between both approaches with differences typically below a few percent. The magnitude of HVP corrections increases with nuclear charge, displaying irregularities that correlate directly with the non-monotonic behavior of nuclear radii. Despite strong relativistic effects at high $Z$ , the ratio of hadronic to muonic vacuum polarization remains remarkably stable, deviating by less than $10%$ from the established $67%$ non-relativistic benchmark value
↳ physics.atom-phnucl-thquant-phPRA(2026)·4 citations
30
Dirac states from the 't Hooft model
Paul Hoyer🇫🇮
The dynamics of a light fermion bound to a heavy one is expected to be described by the Dirac equation with an external potential. The potential breaks translation invariance, whereas the bound state momentum is well defined. Boosting the bound state determines the frame dependence of the light fermion dynamics. I study the Dirac limit of QCD $_{2}$ in the limit of $N_{c} \to \infty$ . The light quark wave function turns out to be independent of the frame of the bound state, up to an irrelevant Lorentz contraction. The discrete bound state spectrum determines corresponding discrete energies of the Dirac equation, which for a linear potential allows a continuous spectrum.
↳ hep-phnucl-thPRD(2026)·0 citations
31
Energy Correlators in Semi-Inclusive Electron-Positron Annihilation
Yu Jiao Zhu🇩🇪
We investigate energy correlators in semi-inclusive electron-positron annihilation as precision probes of parton hadronization dynamics. Using soft-collinear effective theory, we analyze the correlation patterns between the examined hadron and the rest of QCD radiations in both large-angle and small-angle limits, which establishes a direct correspondence with transverse-momentum-dependent fragmentation functions and fragmentation energy correlators. The two complementary regimes encode the transition from perturbative parton branching to nonperturbative confinement, enabling a unified description of hadron formation across all kinematic regimes. Using renormalization group evolution, we obtain joint N $^{3}$ LL/NNLL quantitative predictions for energy correlations both in the sudakov and jet fragmentation region. Our results demonstrate that semi-inclusive energy correlators provide direct, theoretically controlled access to QCD dynamics underlying hadronization, opening new avenues for precision studies at future lepton colliders as well as through reanalyses of archival LEP data.
↳ hep-phnucl-thPRD(2026)·8 citations
32
The N $^{3}$ LO Twist-2 Matching of Helicity TMDs and SIDIS $q_{*}$ Spectrum
Yu Jiao Zhu🇩🇪
We compute the twist-2 matching of transverse momentum dependent (TMD) helicity parton distribution and fragmentation functions at next-to-next-to-next-to-leading order (N $^{3}$ LO) in QCD. This calculation entails the complete set of next-to-next-to-leading order (NNLO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) splitting functions govering the evolution of helicity-dependent parton distribution functions (PDFs) and fragmentation functions (FFs). Within TMD factorization framework, we quantify the impact of radiative corrections by completing the next-to-next-to-next-to-leading logarithmic (N $^{3}$ LL) prediction for lepton-hadron transverse momentum imbalance in semi-inclusive deep inelastic scattering (SIDIS). Our results provide the most precise theoretical input for probing the helicity structure and confined motion of quarks and gluons at future electron-ion collider (EIC).
↳ hep-phnucl-thJHEP(2026)·7 citations
33
The N $^{3}$ LO Twist-2 Matching of Linearly Polarized Gluon TMDs
Yu Jiao Zhu🇩🇪
We compute the twist-2 matching of the transverse-momentum-dependent (TMD) linearly polarized gluon parton distribution and fragmentation functions at next-to-next-to-next-to-leading order (N $^{3}$ LO) in QCD, supplemented by next-to-next-to-leading logarithmic (NNLL) small- $x$ resummation for the gluon TMD fragmentation functions. These results provide high-precision fixed-order and resummed inputs to TMD phenomenology, and constitute essential theoretical ingredients for future studies of the spin structure and three-dimensional tomography of hadrons at the Electron-Ion Collider (EIC).
↳ hep-phnucl-thJHEP(2026)·4 citations
34
Doppler shifted Hawking radiation from acoustic black holes in ultra-relativistic heavy-ion collisions
Sanatan Digal · Ajit M. Srivastava
In a hydrodynamic flow, with flow becoming supersonic at some point, the subsonic-supersonic boundary behaves as the horizon of a black hole. Possibility of detecting Hawking radiation from such acoustic black holes has been investigated in a variety of laboratory systems, ranging from cold atom systems, to condensed matter systems with hydrodynamic flow of electrons, to relativistic heavy-ion collisions (at relatively lower collision energies). Ultra-relativistic heavy-ion collisions, with boost-invariant longitudinal flow of the quark-gluon plasma (QGP) in a wide rapidity window has eluded this remarkable possibility because in this case the black hole horizon is dynamical, moving away from center with sound velocity, leading to infinite red shift of Hawking radiation. We show here that such a conclusion is premature. The QGP flow at very large rapidities, necessarily deviates from Bjroken boost invariant flow. Due to this, an observer close to that region sees black hole horizon with a finite redshift. It leads to non-trivial prediction of Hawking radiation affecting particle momentum distributions for a window of rapidities, leaving near central rapidity regions unaffected.
↳ hep-phgr-qchep-thnucl-ex+10 citations
35
Probing nuclear structure with the Balitsky-Kovchegov equation in full impact-parameter dependence
J. Cepila🇨🇿 · M. Matas🇨🇿 · M. Vaculciak🇨🇿
Building on the newly available solution of the Balitsky-Kovchegov (BK) equation with the full impact-parameter dependence, we extend the study of parton evolution from proton to nuclear targets. Since a key part of the scientific programme for future experimental facilities such as the EIC is to study gluon dynamics and shed new light on the phenomenon of parton saturation, we present predictions for key processes, such as deep-inelastic scattering or the diffractive production of vector mesons, on a variety of nuclear targets. Besides the standard BK equation, we employ its linearised version to identify a promising channel to search for gluon saturation in the nuclear collisions. Furthermore, we implement a tetrahedral model of oxygen to search for deviations from the standard, isotropic, Woods-Saxon approach. In addition to the future colliders, the presented results are also of interest for the current studies of nuclear vector meson production at the LHC.
↳ hep-phnucl-thPRC(2026)·2 citations
36
Softening holographic nuclear matter
Christian Ecker🇩🇪 · Nicolas Kovensky🇦🇷 · Orestis Papadopoulos🇬🇧 · Andreas Schmitt🇬🇧
Baryons in the holographic Witten-Sakai-Sugimoto model are described by instanton solutions on the flavor branes. A commonly used approximation for dense baryonic matter replaces the many-instanton solution by a simpler, spatially homogeneous, ansatz, which requires a discontinuity in the holographic direction of the non-abelian gauge field in order to account for topological baryon number. We point out that the simplest configuration with a single jump - often used in previous studies - results in matter at saturation density that is much stiffer than real-world nuclear matter. This is improved, although not completely remedied, by adding a second jump. We present a systematic discussion of all possible configurations up to four jumps, dynamically computing locations of and behavior at the discontinuities. We find solutions that continuously connect to those based on pointlike baryons, thus, for the first time, establishing a concrete link between the instantonic and homogeneous pictures. This is supported by translating the multi-jump profiles of the gauge field into gauge invariant multi-layer charge distributions. The most important of our novel configurations has a block-like structure in the bulk, becomes pointlike at low density and/or large coupling, and is energetically preferred over all previously studied configurations. Therefore, our work lays the ground for improved predictions from holography for dense nuclear matter in neutron stars.
↳ hep-phhep-thnucl-thJHEP(2026)·2 citations
37
Polarized tau decay and CP violation in ultraperipheral heavy-ion collisions
Amaresh Jaiswal🇮🇳
We investigate the role of $τ$ -lepton polarization in ultraperipheral heavy-ion collisions (UPCs) as a novel application of the intense electromagnetic fields generated in such processes. In particular, we analyze the decay distributions of polarized $τ$ -leptons produced via photon-photon fusion, focusing on both leptonic and semi-leptonic channels. We show that the external magnetic field present in UPCs induces a preferred spin quantization axis, which modifies the angular and energy distributions of $τ$ decay products relative to the standard helicity frame. By formulating the spin polarization along the magnetic field direction, we derive modified polarization-sensitive observables and demonstrate how kinematic selections can retain nonvanishing polarization signals even after ensemble averaging. Furthermore, we propose that the relative polarization of $τ^{-}$ and $τ^{+}$ , accessible through complementary angular ranges of their decay products, serves as a sensitive observable for potential CP-violating effects. This framework provides a pathway for future experimental studies at the LHC and future colliders to exploit polarized $τ$ decays in UPCs as an application of the strong electromagnetic fields to probe new sources of CP violation.
↳ hep-phhep-thnucl-thPLB(2026)·0 citations
38
Role of density profile of sub-GeV dark matter in the properties of dark matter admixed quark stars with Bayesian analysis of dark-NJL model
Debashree Sen🇰🇷 · Atanu Guha🇰🇷 · Jong-Chul Park🇰🇷
We investigate the structural and oscillation properties of dark matter (DM) admixed strange quark stars (DMSQSs). The strange quark matter (SQM) is described with the well-known Nambu-Jona-Lasino (NJL) model and the self-interacting fermionic DM is included in a systematic manner. The self-interaction of DM is of four-Fermi type and the overall DM density is considered as a function of the baryon density of SQM with two free parameters ( $α$ , $ρ_{sc}$ ). This work is the first to consider four-Fermi interactions between fermionic DM and SQM in DMSQSs. Certain experiments like LZ, XENON, DarkSide, CRESST, and LHC have almost ruled out the possibility of contact interaction between SQM and massive DM (in GeV order). Recently, the quest for sub-GeV DM has garnered significant attention. We show that recent astrophysical constraints on the structural properties of compact stars also do not support the presence of massive DM in DMSQSs. On the other hand, we find sub-GeV DM to successfully concur with such observational constraints. We also calculate the fundamental $f$ -mode frequency ( $f_{f}$ ) of the DMSQSs, which shows universality with compactness, mean density, and tidal deformability. Further, we investigate the prospect of detection of $f_{f}$ with respect to the projected sensitivity of upcoming gravitational wave detectors like aLIGO, A+, Cosmic Explorer, and Einstein Telescope. In our DMSQS model, the three free parameters are $α$ , $ρ_{sc}$ , and the ratio of repulsive to attractive interaction in SQM ( $G_{V} / G_{S}$ ), which are optimized by Bayesian analysis in light of various recent astrophysical data.
↳ hep-phastro-ph.HEnucl-th3 citations

Affiliations

first authorsco-authorsvia INSPIRE