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Lei Wang

Publications and source records attributed to Lei Wang.

At least 127 records · Page 7Linked to original sources
arXiv2026

Seeing What Matters: Lesion-Aware High-Resolution Patch Discovery and Fusion for Chest X-ray Report Generation

Despite rapid advances in chest X-ray (CXR) foundation models, most radiology report generation (RRG) systems still rely on heavily downsampled inputs (e.g., 256x256) due to the fixed visual token budgets of pretrained vision encoders, suppressing subtle yet clinically important cues present in native-resolution images. However, enabling high-resolution (high-res) perception remains challenging: naive tiling causes prohibitive token inflation, while global compression suppresses subtle lesions and degrades diagnostic fidelity. Inspired by radiologists' workflow, localizing suspicious regions before detailed high-res assessment. We propose Lesion-Aware High-Resolution Patch Discovery and Fusion for Chest X-ray Reporting (LePaX), the first RRG framework that enables efficient high-res CXR perception (up to 1920x1920) without increasing the vision-token count. LePaX formulates high-res perception as a constrained spatial resolution allocation problem under a fixed token budget and introduces two key components: Learnable Spatial Resolution Allocation (LSRA), which learns a spatial utility map that adaptively allocates limited high-res capacity to diagnostically relevant regions, enabling targeted extraction of high-res patches from native CXRs; and Global-Regional Fusion (GRF), which performs token-preserving region-to-global refinement by projecting high-resolution regional evidence back onto the global feature grid through spatially aligned resolution write-back, avoiding token inflation. Experiments on multiple CXR benchmarks demonstrate that LePaX consistently improves both clinical and linguistic metrics while enabling native-resolution CXR perception with over 10x fewer visual tokens than naive high-res tiling.

cs.CV↗
arXiv2026

Maximum phase-space density of linearly polarized gluon TMDs in the saturation region

We calculate the Sudakov-limited maximum phase-space density associated with the linearly polarized gluon TMD coefficient $h_1^{\perp g}$ in the saturation region. Using Mueller's occupancy argument together with the small-$x$ Weizsäcker-Williams (WW) and dipole gluon distributions of Metz and Zhou, we find $n_{h,{\rm DP}}^{\rm max}=2n_g^{\rm max}\sim2α_s^{-3/2}$ for the dipole distribution in the same phase-space normalization. This dipole result is a process-dependent TMD proxy, not a literal gluon number density. For the WW distribution, the deep-saturation tensor coefficient lacks the logarithmic enhancement needed for the Mueller saddle, so the maximum is pushed toward the saturation boundary. We also perform a numerical Collins-Soper evolution study and find that the $J_2$ Bessel weight in the tensor TMD definition reduces the resolved peak, giving $c_h^{\rm num}\simeq6.6$--$7.1$ for representative EIC scales.

hep-ph↗
arXiv2026

Endpoint Logarithms in the NLO Mueller-Navelet Jet Vertex: Threshold Matching and BLM/MOM Prescription Sensitivity

The endpoint region $ζ\to1$ of the NLO forward jet vertex has not been systematically separated from BFKL energy-scale terms in Mueller-Navelet phenomenology. Starting from the small-cone NLO vertex, we isolate the quark and gluon plus distributions and construct a BFKL-aware threshold matching scheme that preserves exact NLO accuracy. The conservative Scheme-II exponent resums only the ordinary endpoint logarithms and leaves the $χ(n,γ)\ln\bar N$ term in the fixed-order coefficient, avoiding an uncontrolled tower of mixed endpoint-BFKL logarithms. In fixed-baseline CMS tests, this matched vertex is a controlled deformation of an optimized-NLL pointwise BLM/MOM calculation: it moves $R_{21}=C_2/C_1$ in the high-$ΔY$ direction favored by CMS, but it does not improve $C_1/C_0$ or $R_{32}=C_3/C_2$ in the same prescription. A coefficient-projected table-BLM diagnostic improves the absolute moments but lowers $R_{21}$ and is sensitive to the large-$|ν|$ tail. Thus the endpoint matching is internally consistent and phenomenologically informative, while the present setup does not provide a simultaneous description of all five CMS azimuthal observables.

hep-ph↗
arXiv2026

Hyperon-pair spin tomography beyond scalar spin correlations

Spin correlations measured after hadronization probe how quantum information is transported through confinement. We formulate a process-independent spin-tomography framework for $Λ\barΛ$ pairs in which the weak-decay angles determine the full two-spin tensor rather than only its scalar trace. Applied to the short-range STAR correlation in unpolarized $pp\toΛ\barΛX$, the framework shows that the published scalar $P_{Λ\barΛ}$ leaves a continuous density-matrix degeneracy: separable tensor completions and completions that violate the positive-partial-transpose (PPT) criterion can have the same trace. The missing observables are the transverse and longitudinal tensor components and their anisotropy $A_C=C_\perp-C_\parallel$. A local ${}^{3}P_0$ string-breaking benchmark turns the STAR trace into the falsifiable pattern $C_\perp>0$, $C_\parallel<0$, and $A_C>0$. We further show that feed-down must be treated as a tensor response rather than as a universal scalar dilution. In the complementary $e^+e^-$ calibration channel, the same benchmark predicts a centrally enhanced $A_C$ of order $0.3$ in Belle II kinematics, measurable with about $10^4$ selected pairs for nominal spin-transfer parameters. A claim of entanglement requires the reconstructed two-spin density matrix, not the scalar trace alone, to violate the PPT bound.

hep-ph↗
arXiv2026

Nuclear Gluon Gravitational Form Factors and Neutron Skins at the Electron-Ion Collider

Coherent quarkonium production at the Electron--Ion Collider can image the average small-$x$ gluon radius of nuclei, providing a reaction mechanism complementary to parity-violating electron scattering. We develop a calibrated radius-sum-rule framework that connects this gluonic radius to neutron skins and quantify the leading limitations from finite-dipole saturation, nuclear opacity, and instrumental resolution. The central result is that coherent $\Jpsi$ production contains sufficient shape information for a competitive neutron-skin program, but its precision is not limited by luminosity alone. It is instead controlled by the calibration of the nuclear small-$x$ gluon density, while the cleaner $\Ups$ channel remains statistically limited at early EIC luminosities. This framework identifies what an EIC neutron-skin measurement can robustly add to symmetry-energy studies and which theoretical and experimental controls are required before such a measurement can be interpreted as precision nuclear-structure information.

hep-ph↗
arXiv2026

Energy-Flow Moments for Elliptic Gluon Wigner Tomography

The elliptic small-$x$ gluon Wigner distribution correlates transverse momentum with impact parameter, but it is usually accessed through exclusive diffractive dijets whose recoil is sensitive to soft radiation. We propose instead an azimuthal energy-flow moment in DIS dijet production. Within leading-power small-$x$ dijet factorization, its normalized $\cos2ϕ$ moment is a linear projection of the elliptic Wigner harmonic after a calculable kinematic subtraction, while the final-state energy weighting is infrared and collinear safe. In conjugate recoil space a rotationally scalar Sudakov factor evolves the isotropic and elliptic channels through a fixed $J_0/J_2$ Hankel pair without $W_0\to W_1$ leakage. A proof-of-principle calculation gives a per-mille Sudakov-level moment in an unoptimized conservative window, while auxiliary perturbative-window scans reach several per mille. The observable therefore formulates elliptic Wigner tomography as a moment-level energy-flow measurement whose statistical reach can be assessed by simple angular-moment counting.

hep-ph↗
arXiv2026

Collinearly Improved Balitsky-Kovchegov Evolution of the Gluon Wigner Distribution

We study how collinearly improved small-$x$ evolution modifies the elliptic gluon Wigner distribution and its coherent diffractive dijet $\cos2ϕ$ signal. Starting from the $SO(3)$-symmetric Gubser initial condition, we compare fixed-coupling leading-order (LO) BK evolution with the Iancu--Madrigal--Mueller--Soyez--Triantafyllopoulos (IMST) collinearly improved BK prescription, project the evolved dipole to Wigner/GTMD harmonics, and fold the result with photon wave-function hard factors. Within the $SO(3)$-projected framework, the resummed evolution moves the elliptic node and changes the rapidity and hard-scale dependence of $C_2^{\rm coh}=\langle\cos2ϕ\rangle$, rather than acting as a simple normalization shift. The effect is largest in node-sensitive windows but remains visible in broader sign-stable bins. Direct daughter-coordinate RHS tests and direct $(r,b,ϕ)$ evolution quantify the residual projection ambiguity and check the observed trend. Projection-level EIC-like finite-bin estimates show that balanced high-$Δ$ candidate bins offer a better compromise between elliptic signal and denominator weight than the narrow bins with the largest ratio. The unresummed NLO curve is used only as a stability diagnostic; the physical comparison is between LO BK and IMST collinearly improved BK evolution.

hep-ph↗
arXiv2026

Emergent Local Phase-Space Scaling in Small-x Gluon Evolution

Geometric scaling is a central output of nonlinear small-$x$ evolution, but it is less clear whether the same dynamics fixes a probability distribution in transverse phase space. Using fixed-coupling impact-parameter BK evolution in the $SO(3)$-symmetric construction, we build a normalized gluon Husimi phase-space distribution and resolve it with a local coarse graining whose ultraviolet boundary follows $Q_s(Y,b)$. The main result is a distribution-level one: after this $Q_s$-adaptive resolution, the conditional momentum distributions collapse as functions of $k/Q_s(Y,b)$. The conditional entropy then grows with unit slope relative to $\langle\ln Q_s^2\rangle$, as the integrated consequence of that collapse and the two-dimensional momentum measure. Fixed laboratory cutoffs do not show this law, while dense-rapidity, cutoff-window, box-size, regulator-shape, and Husimi-resolution scans keep the $Q_s$-adaptive result stable in the controlled window. Within this fixed-coupling $SO(3)$-BK setting, the result identifies a local phase-space scaling structure of the gluon Husimi distribution rather than a universal law for unregulated global entropy.

hep-ph↗
arXiv2026

Sub-eikonal stress and model dependence of the small-$x$ gluon D-term

The leading-eikonal small-$x$ dipole gives a compact representation of the gluon momentum form factor $A_g(t)$. We show that the same information is not sufficient to determine the gluon stress form factor $C_g(t)$, and hence the gluon D-term. The reason is kinematic and operatorial: in a Drell-Yan frame $A_g(t)$ is projected by $T_g^{++}$, whereas $C_g(t)$ is projected by the symmetric-traceless transverse stress $T_g^{ij}$. This stress projection first appears through next-to-eikonal fields and is represented by gauge-invariant stress-decorated Wilson lines containing $F^{i-}$, $F^{ij}$, or equivalent sub-eikonal target fields. We construct this operator and match it to the local energy-momentum tensor at tree level, obtaining an operator-level no-go statement: the ordinary dipole $S_x(b_\perp,r_\perp)$, or a saturation profile $Q_s^2(x,b)$, does not by itself determine the sign of the small-$x$ gluon D-term. We then give a finite-correlation response model in which a positive kernel generates an anti-aligned response $F^{i-}=-εR_{\rm NE}F^{i+}$, so that $Λ_{\rm NE}>0$ and $D_g(0)<0$ within that response class. A Gaussian benchmark and numerical scans over Gaussian, Woods-Saxon, power-edge, and McLerran-Venugopalan (MV)-inspired profiles show a stable negative forward D-term for this anti-aligned model, together with the expected core-shell pressure pattern. The gluon D-term is therefore a next-to-eikonal stress probe, not a universal leading-eikonal saturation observable.

hep-ph↗
arXiv2026

GeoSearcher: Anchor-Guided Progressive Reasoning for Remote Sensing Visual Grounding with Process Supervision

Recent multimodal large language models (MLLMs) have shown strong cross-modal understanding and coordinate generation abilities in visual grounding. However, transferring these abilities to remote sensing visual grounding (RSVG) remains challenging. High-resolution remote sensing images usually cover large-scale scenes, where targets are often extremely small and surrounded by numerous visually similar distractors. Meanwhile, queries often contain multiple clues, such as reference objects, spatial relations, and target attributes. Existing MLLM-based methods usually formulate RSVG as one-step coordinate generation, which may lead to unstable predictions for small-object localization and complex queries. To address these challenges, we propose GeoSearcher, which reformulates RSVG as an anchor-guided progressive reasoning process and realizes it through two coupled stages: Anchor-Centric Reasoning Supervised Fine-Tuning (ACR-SFT) and Process-Faithful Group Relative Policy Optimization (PF-GRPO). In ACR-SFT, anchor-centric reasoning data are used to teach the model to represent key visual clues as anchors and progressively integrate location, relational, and attribute clues around them. In PF-GRPO, Process-Aware Reward (PAR) and Reasoning-Informative Sample Selector (RISS) further optimize this reasoning behavior by jointly evaluating key reasoning steps and target localization, while focusing training on samples that are more beneficial for improving progressive reasoning. Through this design, GeoSearcher transforms large-scale visual search into a more constrained local reasoning process. Extensive experiments on DIOR-RSVG, OPT-RSVG, and VRS-Bench show that GeoSearcher outperforms existing state-of-the-art methods. The project will be released at https://github.com/wangdianyu954-xixi/GeoSearcher.

cs.CV↗
arXiv2026

Spatially variant arbitrary polarization shaping for optical skyrmions generation

Polarization is fundamental degree of freedom of light, crucial for applications from imaging to quantum optics. Although numerous methods can spatially manipulate the polarization orientation, e.g., for generating vector beam, achieving simultaneous, spatially resolved control of both the orientation (ψ) and ellipticity (\c{hi}) remains challenging. Here, we present an efficient and compact platform to generate spatially variant arbitrary polarization states, e.g., optical skyrmions, in free space, using cascaded spatially variant waveplates in a single silica glass plate via ultrafast laser direct writing. We propose two configurations: (1) a spatially variant half-waveplate (S-HWP) and followed by a quarter-waveplate (S-HWP); and (2) two cascaded spatially variant quarter-waveplates (S-QWPs). Design rules linking the target polarization parameters (orientation ψ and ellipticity \c{hi}) to the fast-axis distributions enable spatially resolved arbitrary polarization control. Using these devices, we realize Néel-, Bloch-, and anti-skyrmions of different orders (e.g., second and fourth) and n-π textures (2π and 3π), with polarization-resolved measurements in excellent agreement with simulations. We further demonstrate 3 by 3 arrays comprising either identical or hybrid skyrmions. This approach enables the realization of spatially variant arbitrary polarization state and scalable skyrmion lattices.

physics.optics↗
arXiv2026

On the regularity of irreducible subgroups of finite classical groups

Let $G$ be a finite group and let $τ= (H_1, \ldots, H_t)$ be a $t$-tuple of core-free subgroups of $G$. We say that $τ$ is regular if $G$ contains elements $g_1, \ldots, g_t$ such that $\bigcap_i H_i^{g_i} = 1$, which is equivalent to the existence of a regular $G$-orbit on the Cartesian product $G/H_1 \times \cdots \times G/H_t$. Regular tuples were first investigated by Anagnostopoulou-Merkouri and Burness in a paper from 2024, partly motivated by the aim of seeking a natural generalisation of the classical and widely studied concept of a base for a transitive permutation group, which aligns with the special case where the $H_i$ are pairwise conjugate subgroups. In this paper, we focus on the case where $G$ is a finite almost simple classical group and each $H_i$ is a maximal subgroup contained in Aschbacher's collection $\mathcal{S}$ of irreducibly embedded subgroups. Our main theorem determines all the non-regular $t$-tuples of this form with $t \geqslant 2$, which extends earlier work by Burness, Guralnick and Saxl in the base size setting. In particular, we deduce that every pair of maximal subgroups in $\mathcal{S}$ is regular if $n \geqslant 15$, where $n$ is the dimension of the natural module for the socle of $G$, and this lower bound is best possible.

math.GR↗
arXiv2026

Measurement of solar $pp$ neutrino flux with the new PandaX-4T data

We report a new measurement of the solar proton--proton ($pp$) neutrino flux via neutrino--electron elastic scattering using the PandaX-4T Run 2 data set collected between 2024 and 2026, corresponding to an exposure of 1.9 tonne$\cdot$yr. Before Run 2 data taking, the detector underwent a series of upgrades to improve its response and background conditions. Time variations of radioactive noble-gas impurities are constrained using the physics data themselves, complemented by measurements from the gas-assay system. The analysis introduced improvements in the data processing chain, detector response characterization, and background models. A blind spectral analysis was then performed on the electronic-recoil data across a wide energy range from 20 to 1000 keV. In combination with the Run 0 data published earlier, the fitted $pp$ flux is $(8.5 \pm 3.5)\times 10^{10}$ $\mathrm{cm^{-2}s^{-1}}$, consistent with the prediction of the Standard Solar Model. With a statistical significance of $2.2σ$ above background, this marks the first positive indication of solar $pp$ neutrino--electron scattering below an electronic-recoil energy of 165 keV.

hep-ex↗
arXiv2026

Performance of FBK VUV-HD3 and HPK VUV4 SiPMs in the Light-only Liquid Xenon (LoLX) Detector

Silicon Photomultipliers (SiPMs) are a critical technology for the next generation of rare-event search experiments using liquid xenon (LXe). LXe scintillation is emitted primarily in the vacuum-ultraviolet (VUV), requiring photosensors with high VUV detection efficiency under cryogenic operating conditions. Direct characterization of VUV-sensitive SiPMs in LXe is therefore important for informing detector design and comparing device response. This work presents a direct comparison of Fondazione Bruno Kessler (FBK) VUV-HD3 and Hamamatsu (HPK) VUV4 SiPMs operated simultaneously within the Light-only Liquid Xenon (LoLX) detector. Using data collected with gamma sources placed outside the detector, we characterized the relative performance of these photosensors. Our analysis reveals that under these operating conditions, the HPK SiPMs observe 33-38% less light than the FBK devices, a larger difference than predicted by standard PDE models in vacuum measurements. We show that this discrepancy is resolved by an angular and wavelength dependent PDE model incorporating surface shadowing effects into our optical simulation, which then accurately reproduces the experimental data. This finding has significant implications for the selection and implementation of photosensors in future large-scale LXe detectors.

physics.ins-det↗
arXiv2026

RefAlign: Representation Alignment for Reference-to-Video Generation

Reference-to-video (R2V) generation is a controllable video synthesis paradigm that constrains the generation process using both text prompts and reference images, enabling applications such as personalized advertising and virtual try-on. In practice, existing R2V methods typically introduce additional high-level semantic or cross-modal features alongside the VAE latent representation of the reference image and jointly feed them into the diffusion Transformer (DiT). These auxiliary representations provide semantic guidance and act as implicit alignment signals, which can partially alleviate pixel-level information leakage in the VAE latent space. However, they may still struggle to address copy--paste artifacts and multi-subject confusion caused by modality mismatch across heterogeneous encoder features. In this paper, we propose RefAlign, a representation alignment framework that explicitly aligns DiT reference-branch features to the semantic space of a visual foundation model (VFM). The core of RefAlign is a reference alignment loss that pulls the reference features and VFM features of the same subject closer to improve identity consistency, while pushing apart the corresponding features of different subjects to enhance semantic discriminability. This simple yet effective strategy is applied only during training, incurring no inference-time overhead, and achieves a better balance between text controllability and reference fidelity. Extensive experiments on the OpenS2V-Eval benchmark demonstrate that RefAlign outperforms current state-of-the-art methods in TotalScore, validating the effectiveness of explicit reference alignment for R2V tasks.

cs.CV↗
arXiv2026

Neural Canonical Transformation for the Spectra of Fluxional Molecule CH5+

Protonated methane, CH5+, is a highly fluxional molecule with large spatial motions of the hydrogen atoms. The molecule's anharmonic effects and the delocalized wavefunction of the hydrogen atoms significantly affect the excitation spectrum of the molecule. The neural canonical transformation (NCT) approach, which we previously developed to solve the vibrational spectra of molecules and solids, is a powerful method that effectively treats nuclear quantum effects and anharmonicities. Using NCT with wavefunctions in atomic coordinates rather than normal coordinates, we successfully calculate the ground and excited states of CH5+. We found that the wavefunctions for the ground state, as well as for low- and high-energy excited states, show preferences for the three stationary points on the potential energy surface. This work extends the applicability of the NCT approach for calculating excited states to fluxional molecules without fixed geometry.

physics.chem-ph↗
arXiv2026

AgentX: Towards Agent-Driven Self-Iteration of Industrial Recommender Systems

Recommendation algorithm iteration is moving from an artisanal, engineer-bound process toward an industrialized research loop, but this transition remains blocked by a structural execution bottleneck: the idea-to-launch cycle still depends on human engineers to generate hypotheses, modify production code, launch A/B experiments, and attribute online results. Innovation therefore scales linearly with headcount rather than compounding with evidence, compute, and accumulated experimental knowledge. We present AgentX, a production-deployed multi-agent system that fundamentally restructures this production function. AgentX operates as a self-evolving development engine: it autonomously generates, implements, evaluates, and learns from recommendation experiments at a scale and pace that no manual workflow can sustain. The system orchestrates four tightly coupled stages in a closed loop. A Brainstorm Agent synthesizes evidence from historical experiments, system architecture, data analysis, and external research into ranked, executable proposals. A Developing Agent translates each proposal into production-ready code through repository-grounded generation and multi-dimensional reliability verification. An Evaluation Agent conducts safe online rollout with guardrail-vetoed A/B judgment, converting both successes and failures into structured knowledge assets. A Harness Evolution layer (SGPO) then distills execution trajectories into semantic-gradient updates that continuously sharpen the agents themselves -- making the system not merely automated, but self-improving.

cs.AI↗
arXiv2026

Symmetry-Selective Strain Control of Spin-Momentum Locking and Spin Transport in Two-Dimensional Pentagonal Altermagnets

Altermagnets are compensated magnets featuring momentum-dependent nonrelativistic spin splitting generated by nontrivial operations connecting opposite-spin sublattices. A direct symmetry-based route to control this spin splitting is to modify the real-space operations that define the altermagnetic spin-momentum locking (SML). Here, we develop a strain-resolved symmetry framework for two-dimensional pentagonal altermagnets, classifying whether uniaxial and shear strain tensors preserve, reconstruct, or eliminate the SML. Using the above criterion combined with first-principles screening, we identify 94 stable altermagnetic candidates from 3330 materials. These candidates cover all type-III spin Laue groups of orthorhombic lattices and are classified into three strain-response types: Type-I preserves the SML; Type-II reconstructs the SML through partial symmetry breaking while retaining essential altermagnetic features; and Type-III destroys the altermagnetic SML. Representative materials further demonstrate this classification: ferroelastic $α$-CoS$_2$ exhibits ferroelastically switchable SML and reverses the sign of the off-diagonal spin conductivity; shear-strained \(α\)-CoP\(_2\) undergoes a \(g\)- to \(d\)-wave reconstruction of the SML, activating off-diagonal spin conductivity; and uniaxially strained FeSSe realizes strain-selected spin-valley transport. This work provides theoretical and material guidance for strain-controlled transport in two-dimensional orthorhombic altermagnets.

cond-mat.mtrl-sci↗