arXiv subjects

Chao Chen

Publications and source records attributed to Chao Chen.

At least 19 recordsLinked to original sources

arXiv2026

DINO-Med: A Unified Patch-Based Adaptation Framework for Multi-Modal Medical Image Analysis Applied to Liver Fibrosis Staging

Adapting natural-image foundation models like DINOv3 to multi-modal medical imaging is challenging due to the significant domain gap between natural color images and multi-channel medical scans. We present a unified, patch-based framework that processes raw multimodal imaging through training-free registration, automated localization, and mask-filtered patch extraction. This architecture culminates in a hierarchical strategy that aggregates patch-level insights into subject-level diagnostics. Using liver fibrosis staging as a case study, we evaluate four patch-level feature representations: handcrafted Radiomics features, learned ResNet features, pre-trained foundation model SAM-Med2D features, and frozen DINOv3 features. To ensure a controlled comparison, all models utilize the same lightweight MLP head and are evaluated across both rigid and deformable registration settings. Our training protocol focuses on mild fibrosis (S1) and cirrhosis (S4) classes only, enabling a single classifier to address both substantial fibrosis detection and cirrhosis staging. Evaluated via 10 random train (90%)/ test (10%) splits on 360 subjects from the CARE 2025 Liver Track 4 cohort, our DINOv3-based framework significantly outperforms all baselines, achieving the best classification accuracy of 78.4% for S1 and 75.8% for S4.

cs.CV↗

arXiv2026

Search for the doubly Cabibbo-suppressed decays $D^0\to K^+\pi^-\eta^\prime$ and $D^+\to K^+\pi^0\eta^\prime$

We present the first search for the doubly Cabibbo-suppressed decays $D^0\to K^+\pi^-\eta^\prime$ and $D^+\to K^+\pi^0\eta^\prime$ using an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 20.3 fb$^{-1}$, collected at a center-of-mass energy of 3.773 GeV with the Beijing Spectrometer III (BESIII) detector at the Beijing Electron-Positron Collider II (BEPCII). No significant signals are observed, and the upper limits on their decay branching fractions are set to be $3.0\times 10^{-5}$ and $2.1\times 10^{-5}$ at the 90% confidence level, respectively. By combining these results with the world-average branching fractions of the corresponding Cabibbo-favored decays, upper limits at the 90% confidence level are obtained on the ratios of doubly Cabibbo-suppressed to Cabibbo-favored branching fractions. The limits are determined to be $1.6\times \tan^4\theta_C$ and $3.7\times \tan^4\theta_C$ for $D^0\to K^+\pi^-\eta^\prime$ and $D^+\to K^+\pi^0\eta^\prime$, respectively, where $\theta_C$ denotes the Cabibbo mixing angle.

hep-ex↗

arXiv2026

Parameterized and Streaming Algorithms for Euclidean Fair $k$-Center Clustering

Motivated by the growing importance of fairness in machine learning, fair $k$-center clustering has attracted considerable research attention as a fundamental problem. In this problem, a dataset is partitioned into $m$ disjoint groups, and the objective is to select $k$ data points as centers, subject to upper bounds on the number of centers chosen from each group, aiming to minimize the maximum distance between any data point and its assigned center. Focusing on Euclidean spaces, which are ubiquitous in machine learning applications, we first develop a parameterized approximation algorithm for Euclidean fair $k$-center with an approximation ratio of $2.732$. By incorporating this algorithm as a post-processing stage into a one-pass streaming framework for large-scale data, we obtain an approximation ratio of $4.464$. These ratios can be further respectively improved to $2.414$ and $3.828$ with a runtime exponential on $k$. To ensure polynomial-time complexity, we further design a one-pass streaming algorithm with an approximation ratio of $4.732$, which can be further improved to $4.42$, outperforming the state-of-the-art ratio. Finally, extensive experiments show that our methods significantly outperform state-of-the-art approaches in terms of clustering accuracy.

cs.LG↗

arXiv2026

Measurement of CP Asymmetry Parameters and Polarization Correlations in $\Omega^{-}\bar{\Omega}^{+}$ Pairs

Using $(2.71 \pm 0.01) \times 10^9$ $\psi(3686)$ events collected with the BESIII detector, a joint full angular distribution analysis is carried out for the process $\psi(3686) \to \Omega^-(\to\Lambda K^-) \, \bar{\Omega}^{+}(\to \bar{\Lambda}K^+)$. The first simultaneous measurement of the weak decay parameters $\phi_{\Omega^{-}}$ and $\phi_{\bar{\Omega}^{+}}$ for $\Omega^- \to K^-\Lambda$ and $\bar{\Omega}^+ \to K^+\bar{\Lambda}$ is performed, yielding the first result for the CP-sensitive observable, $\phi_{\rm CP} = (-0.004 \pm 0.055 \pm 0.017)~\text{rad}$, where the first and second uncertainties are statistical and systematic, respectively. This further enables the extraction of the weak and strong phase differences between the $P$- and $D$-wave amplitudes: $(\xi_D - \xi_P) = (-0.15 \pm 2.25 \pm 0.69)~\text{rad}$ and $(\delta_D - \delta_P) = (-0.97 \pm 0.88 \pm 0.34)~\text{rad}$. Additionally, the polarization correlations between $\Omega^{-}$ and $\bar{\Omega}^{+}$ are measured.

hep-ex↗

arXiv2026

Study of $K_{S}^{0}$-$K_{L}^{0}$ asymmetry in the decays $D^0 \to K_{S}^{0}\omega $ and $D^0 \to K_{L}^{0} \omega $

Based on $e^+ e^-$ annihilation data corresponding to an integrated luminosity of 7.93~$fb^{-1}$ collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider, the absolute branching fractions of the decays $D^0 \to K_{S}^{0} \omega$ and $D^0 \to K_{L}^{0} \omega $ are measured to be $(11.79 \pm 0.19 \pm 0.26 \pm 0.47) \times 10^{-3}$ and ($10.84 \pm 0.14 \pm 0.23 \pm 0.44) \times 10^{-3}$, respectively. The $K_{S}^{0}- K_{L}^{0}$ branching-fraction asymmetry of these two decays is $R(D^0,K_{S,L}^{0} \omega) = \frac{\mathcal{B}(D^0 \to K_{S}^{0} \omega) - \mathcal{B}(D^0 \to K_{L}^{0}\omega )}{\mathcal{B}(D^0 \to K_{S}^{0} \omega) + \mathcal{B}(D^0 \to K_{L}^{0} \omega)} =(4.2 \pm 1.0 \pm 0.9 \pm 2.8)\%$. Here, the first uncertainties are statistical, the second systematic, and the third arise from the interference between $D^0 \to K_{S,L}^{0} \omega$ and the non-resonant $D^0 \to \pi^+ \pi^- \pi^0 K_{S,L}^{0}$ processes.

hep-ex↗

arXiv2026

Search for the baryonic decay $ D_{s}^{*+} \to \ p \bar{n} $

The first search for the baryonic decay $ D_{s}^{*+} \to \ p \bar{n} $ is performed using $e^+e^-$ collision data taken at center-of-mass energies between 4.128 and 4.226 GeV, collected by the BESIII experiment and corresponding to an integrated luminosity of 7.33 fb$^{-1}$. No significant signal is observed, and an upper limit on the branching fraction is set to be $1.3\times 10^{-4}$ at the $90\%$ confidence level.

hep-ex↗

arXiv2026

Observation of $\psi(3686)\to p K^- K_S^0 \bar \Xi^0+c.c.$

Using a sample of $(2.712 \pm 0.014) \times 10^{9}$ $\psi(3686)$ events collected with the BESIII detector, the decay of $\psi(3686)\to p K^- K_S^0 \bar \Xi^0+c.c.$ is observed for the first time with a statistical significance of $11.5\sigma$. The branching fraction of this decay is measured to be $(2.84\pm 0.40\pm 0.25) \times 10^{-6}$, where the first and second uncertainties are statistical and systematic, respectively. This measurement extends the experimental information on rare multi-strange $\psi(3686)$ decays and provides an experimental reference for future studies of related decay modes.

hep-ex↗

arXiv2026

The Analytical Solutions of Dyonic Black Holes in Einstein-Euler-Heisenberg Theory

Recently, we constructed analytical purely electric and purely magnetic black-hole solutions in Einstein--Euler--Heisenberg theory, while the corresponding dyonic solutions were obtained numerically \cite{Luo:2026srx}. Motivated by the recent analytical construction of a dyonic black hole at the special coupling locus $b=a/2$ \cite{Ahmed:2026ufj}, we revisit the general dyonic sector. We show that exact analytical dyonic black-hole solutions can be constructed for nonlinear couplings satisfying $2b>a$, without imposing the restriction $b=a/2$. The mass function is expressed in closed form in terms of the Lauricella hypergeometric function. In particular, our construction yields an exact dyonic solution for the Euler--Heisenberg coupling $b=7a/4$. The solution of Ref.~\cite{Ahmed:2026ufj} is recovered in the limiting case $2b\rightarrow a$.

gr-qc↗

arXiv2026

Measurement of inelastic scattering $\Lambda(\overline{\Lambda})+p\to\Sigma^{0}(\overline{\Sigma}^{0})+p$ via $e^+e^-\to J/\psi\to\Lambda\overline{\Lambda}$

Using a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events collected with the BESIII detector, we investigate the inelastic scattering processes $\Lambda+p\to\Sigma^{0}+p$ and $\overline{\Lambda}+p\to\overline{\Sigma}^{0}+p$, exploiting hyperons from $J/\psi\to\Lambda\overline{\Lambda}$ decays as an effective beam and the beam-pipe materials as targets. The processes $\Lambda+{}^{9}\mathrm{Be}\to\Sigma^{0}+p+{}^{8}\mathrm{Li}$ and $\overline{\Lambda}+{}^{9}\mathrm{Be}\to\overline{\Sigma}^{0}+p+{}^{8}\mathrm{Li}$ are measured at a hyperon momentum of $1.074~\mathrm{GeV}/c$, with cross sections of $(10.1\pm1.4_{\rm stat}\pm0.7_{\rm syst})$ mb and $(1.7\pm0.6_{\rm stat}\pm0.4_{\rm syst})$ mb, respectively. Under the assumption of surface-dominated hyperon-nucleus scattering, these measurements are used to extract the corresponding proton-target cross sections. Independently, direct measurements using the hydrogen component of the beam-pipe oil yield $(3.2\pm1.1_{\rm stat}\pm0.5_{\rm syst})$ mb for $\Lambda+p\to\Sigma^{0}+p$ and $(1.5\pm0.5_{\rm stat}\pm0.1_{\rm syst})$ mb for $\overline{\Lambda}+p\to\overline{\Sigma}^{0}+p$, consistent with the indirect determinations. The combined cross sections are $(4.7\pm0.7)$ mb and $(1.1\pm0.3)$ mb, respectively. The $\overline{\Lambda}+p\to\overline{\Sigma}^{0}+p$ signal constitutes the first evidence for anti-hyperon inelastic scattering with baryonic final states, with a significance of $3.1\sigma$. The pronounced difference between the $\Lambda p$ and $\overline{\Lambda}p$ inelastic scattering cross sections provides new experimental constraints on hyperon-nucleon and anti-hyperon-nucleon interactions.

hep-ex↗

arXiv2026

Attosecond Reconstruction of Strain Tensors via Electronic Fingerprints

We demonstrate an attosecond transient absorption spectroscopy (ATAS) scheme for reconstructing strain tensors in two-dimensional materials. Using strained graphene as a prototype system, we show that the fishbone structures in ATAS serve as distinctive spectral fingerprints of strain, where strain-induced shifts and splittings of van Hove singularities encode the magnitude and orientation of the strain tensor, respectively. By combining density-matrix simulations with analytical modeling, we establish a direct mapping between transient absorption spectra and strain tensors, enabling accurate retrieval of lattice deformation from ultrafast electronic responses. Our work introduces an attosecond spectroscopic paradigm for ultrafast strain metrology, where electronic fingerprints replace conventional structural probes for sensing lattice deformation in quantum materials.

cond-mat.mtrl-sci↗

arXiv2026

Evidence for $\eta_{c}(2S)\to p\bar{p}\pi^{+}\pi^{-}\pi^{0}$ and observation of $\chi_{cJ} \to p\bar{p}\pi^{+}\pi^{-}\pi^{0}$

Using $(2.712\pm0.014)\times 10^9$ $\psi(3686)$ events collected by the BESIII detector at the BEPCII collider, the $\psi(3686) \to \gamma p\bar{p}\pi^+\pi^-\pi^0$ process is investigated. Evidence for the decay of $\eta_{c}(2S)\to p\bar{p}\pi^{+}\pi^{-}\pi^{0}$ is found with a signal significance of 3.3$\sigma$. The product of branching fractions of $\mathcal{B}[\psi(3686)\to \gamma \eta_{c}(2S)]\times\mathcal{B}[\eta_{c}(2S)\to p\bar{p}\pi^{+}\pi^{-}\pi^{0}]$ is determined to be $(3.4\pm0.5\pm0.8) \times 10^{-6}$, where the first uncertainty is statistical and the second systematic. The hadronic decays of $\chi_{cJ} \to p\bar{p}\pi^+\pi^-\pi^0$$~(J=0,1,2)$ are observed, and their branching fractions are measured to be $\mathcal{B}(\chi_{c0}\to p\bar{p}\pi^{+}\pi^{-}\pi^{0})=(4.79\pm 0.01\pm0.40) \times 10^{-3}$, $\mathcal{B}(\chi_{c1}\to p\bar{p}\pi^{+}\pi^{-}\pi^{0})=(2.13\pm 0.01\pm0.17) \times 10^{-3}$, and $\mathcal{B}(\chi_{c2}\to p\bar{p}\pi^{+}\pi^{-}\pi^{0})=(3.72\pm 0.01\pm0.29) \times 10^{-3}$, respectively. Furthermore, the branching fractions for the intermediate processes $\chi_{cJ}\to p\bar{p}\omega$ are updated with significantly improved precision: $\mathcal{B}(\chi_{c0}\to p\bar{p}\omega)=(5.76\pm0.01\pm0.42)\times10^{-4}$, $\mathcal{B}(\chi_{c1}\to p\bar{p}\omega)=(1.85\pm0.01\pm0.13)\times10^{-4}$, and $\mathcal{B}(\chi_{c2}\to p\bar{p}\omega)=(4.51\pm0.01\pm0.33)\times10^{-4}$, respectively.

hep-ex↗

arXiv2026

OmniAlign: A Unified Multilingual Aligner for Word and Sentence Alignment

Cross-lingual sequence alignment is fundamental for building and exploiting parallel corpora, spanning mappings from documents and sentences down to words and subwords. Existing tools, however, typically specialize in a single granularity, so practitioners often need separate systems for word- and sentence-level alignment---especially in multilingual and long-text settings. We present OmniAlign, a unified multilingual aligner that supports both word-level and sentence-level alignment with a single lightweight model. Built on an encoder-only backbone with strong long-context modeling, OmniAlign induces word alignments from contextualized token similarity matrices, and obtains document-level $m$--$n$ sentence alignments via sentence embeddings combined with dynamic programming. To balance fine-grained alignment accuracy and sentence-representation quality, we use a four-stage training pipeline: alignment-oriented continued pre-training, self-supervised learning, supervised fine-tuning on human annotations, and sentence-embedding distillation from a strong multilingual teacher. Experiments show that OmniAlign achieves highly competitive performance on both word- and sentence-alignment benchmarks and generalizes well to unseen language pairs. Surprisingly, later-stage supervised fine-tuning on short texts further improves alignment quality while retaining the long-context understanding acquired in earlier training, keeping the model robust on long-text word alignment. \normalsize {\color{blue}\textbf{Code}: https://github.com/MilkDargon/OmniAlign}\par {\color{blue}\textbf{Model}: https://huggingface.co/WPS-Qingqiu/OmniAlign}

cs.CL↗

arXiv2026

Measurement of Branching Fraction and Transition Magnetic Moment of the Hyperon Dalitz Decay $\Sigma^0 \rightarrow \Lambda e^+e^-$

Based on a data sample of 10 billion $J/\psi$ events collected with the BESIII detector operating at the BEPCII collider, the Dalitz decay $\Sigma^0 \rightarrow \Lambda e^+e^-$ is studied experimentally for the first time. The $\Sigma^0$ hyperons are produced through the process $J/\psi \rightarrow \Sigma^0\bar{\Sigma}^0$ and analyzed using a double-tag method. The absolute branching fraction is measured to be $\mathcal{B}(\Sigma^0 \rightarrow \Lambda e^+e^-) = (6.34 \pm 0.25_{\rm stat.} \pm 0.23_{\rm syst.}) \times 10^{-3}$. This result shows a $2\sigma$ discrepancy from the theoretical calculation quoted in the PDG, where the uncertainties are statistical and systematic, respectively. In addition to the branching fraction, the transition magnetic moment $\mu$ is determined to be $(1.74 \pm 0.03_{\rm stat.} \pm 0.09_{\rm syst.})\,\mu_N$, where $\mu_N=e/(2m_p)$ represents the nucleon magnetic moment, providing valuable insight into the intrinsic structure of the $\Sigma^0$ hyperon.

hep-ex↗

arXiv2026

Multi-Granularity Sentiment Integration for LLM-Based Multimodal Sentiment Analysis

Multimodal sentiment analysis (MSA) aims to predict sentiment polarity and intensity from heterogeneous inputs such as text, audio, and vision. While large language models (LLMs) offer strong semantic priors for MSA, effectively incorporating audio and visual signals effectively remains challenging. A key challenge is that audio and visual sentiment cues evolve over different temporal scales, yet many LLM-based methods compress these signals through shallow projection or coarse pooling before fusing them with text, which can weaken cross-modal alignment and erase fine-grained affective information. We propose MGSI, a multi-granularity sentiment integration framework for LLM-based MSA. MGSI first encodes audio and visual streams at short-, medium-, and long-range temporal scales, preserving both local variations and global affective trends. It then refines non-text features through text-guided alignment, and applies polarity- and intensity-aware enhancement to better handle ambiguous and near-neutral samples. The resulting multimodal representation is finally compressed into a small set of pseudo-tokens for efficient conditioning of a frozen LLM. Experiments on four public benchmarks show that MGSI substantially outperforms frozen-LLM baselines and remains competitive with strong multimodal methods. Further ablation and sensitivity analyses support the effectiveness of multi-granularity temporal modeling, text-guided refinement, and adaptive sentiment calibration.

cs.LG↗

arXiv2026

First measurements of the branching fractions of $J/\psi$ and $\psi(3686) \to \Sigma^{0} \bar{\Sigma}^{0}\eta$

Based on $(10087 \pm 44) \times 10^6$ $J/\psi$ and $(2712 \pm 14) \times 10^6$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII collider, the hadronic decays $J/\psi \to \Sigma^{0} \bar{\Sigma}^{0} \eta$ and $\psi(3686) \to \Sigma^{0} \bar{\Sigma}^{0} \eta$ are observed for the first time. The corresponding branching fractions are measured to be $\mathcal{B}(J/\psi \to \Sigma^{0} \bar{\Sigma}^{0}\eta)= (7.5 \pm 0.3 \pm 0.8) \times 10^{-5}$ and $\mathcal{B}(\psi(3686) \to \Sigma^{0} \bar{\Sigma}^{0}\eta)= (1.3\pm 0.1 \pm 0.1) \times 10^{-5}$, respectively, where the first uncertainties are statistical, and the second systematic. The ratio $\text{Q} \approx \frac{\mathcal{B}(\psi(3686) \to \Sigma^{0} \bar{\Sigma}^{0} \eta)}{\mathcal{B}(J/\psi \to \Sigma^{0} \bar{\Sigma}^{0} \eta)}$ is determined to be $(17.3 \pm 1.5 \pm 1.7)\%$, which is con sistent with the 12\%-rule within 3.0$\sigma$.~No significant intermediate states or threshold enhancements are observed in the $\Sigma^0$($\bar{\Sigma}^{0}$)$\eta$ and $\Sigma^0$$\bar{\Sigma}^{0}$ invariant mass spectra.

hep-ex↗

arXiv2026

High-precision measurement of the space-like $\eta^\prime$ transition form factor

Using a data sample corresponding to an integrated luminosity of $20.3\ \text{fb}^{-1}$, collected with the BESIII detector at a center-of-mass energy of $3.773\ \text{GeV}$ at the BEPCII collider, we report a precision measurement of the product $Q^2|F(Q^2)|$, where $F(Q^2)$ is the single-virtual space-like transition form factor of the $\eta'$ meson and $Q^2$ is the squared momentum transfer of the tagged virtual photon. The transition form factor is extracted from the differential Born cross section of the two-photon fusion processes $e^+e^- \to e^+e^-\gamma\gamma^* \to e^+e^-\eta^\prime$ using a single-tag technique, where only one scattered lepton is detected. The measurement covers $Q^2 \in [0.1, 6.0]$ GeV$^2$, achieving unprecedented precision, better than $3.0\%$ for $Q^2 < 1.5$ GeV$^2$, and providing the first direct determination at $Q^2 < 0.3$ GeV$^2$.

hep-ex↗

arXiv2026

Model the Edit, Not the Image: Visual Autoregressive Editing from a Source-Centric Perspective

Next-scale visual autoregressive models (VARs) have emerged as a powerful generative paradigm, producing high-quality images through efficient coarse-to-fine prediction. However, their potential for text-guided image editing remains largely underexplored. Existing training-free VAR editing approaches often formulate editing as target-conditioned regeneration guided or constrained by the source image, and may rely on inversion, test-time optimization, attention control, or user-provided masks. This generation-centric formulation does not fully exploit the multiscale source representations provided by VARs and may introduce additional computation or intervention. We instead take a source-centric perspective on VAR editing, in which the encoded source image tokens serve as the primary visual state and the editing process focuses on condition-induced changes. Based on this perspective, we propose \textbf{EditMod}, which compares source- and target-conditioned predictions under a shared autoregressive context, treats their difference as a scale-wise editing direction, and applies it as a residual update to source tokens at selected scales. Experiments show that EditMod achieves leading source-image fidelity while maintaining strong text alignment, and completes end-to-end editing of a 1K image in only 1.57 seconds on a single A100 GPU without per-image preparation.

cs.CV↗

arXiv2026

Search for the charged lepton flavour violating decay $\eta'\to e\mu$

Based on $(8998\pm40)\times10^6$ $J/\psi$ events collected in $e^+e^-$ collisions at $\sqrt{s} = 3.097$ GeV with the BESIII detector, we present a search for the charged lepton flavour violating decay $\eta'\to e\mu$ with $J/\psi\to\gamma\eta'$. No significant signal is observed, and an upper limit on its decay branching fraction is set to be $6.3\times10^{-7}$ at the 90% confidence level, improving the previous best result by nearly three orders of magnitude.

hep-ex↗