arXiv subjects

En Wang

Publications and source records attributed to En Wang.

At least 19 recordsLinked to original sources

arXiv2026

Revisiting the $\Lambda_c^+ \to n\pi^+\eta$ decay in light of the BESIII measurement

Motivated by the latest BESIII measurements on $\Lambda_c^+\to n\pi^+\eta$, we perform a systematic theoretical study of this decay. We take into account contributions from the $N(1535)$ state dynamically generated by $S$-wave pseudoscalar meson-octet baryon interactions, the $a_0(980)$ resonance originating from the $S$-wave pseudoscalar meson-pseudoscalar meson interactions, together with the intermediate states $N(1440)$ and $a_2(1320)$. Our results indicate that $a_0(980)$ provides a significant contribution to this process. The inclusion of $a_2(1320)$ hardly improves the fitting quality, while the nucleon resonances play a crucial role in describing the experimental behavior of the $\pi^+\eta$ invariant mass spectrum in both low and high energy regions. Restricted by insufficient experimental statistics and a coarse bin size of 33 MeV, the precise contribution fraction of $a_0(980)$ cannot be reliably extracted. We propose future higher-precision and higher-statistics experimental measurements of $\Lambda_c^+\to n\pi^+\eta$, which can help reveal the intrinsic nature of $a_0(980)$ and quantify the roles of different excited nucleon states in this decay.

hep-ph↗

arXiv2026

Identifying $\Sigma(1380)$ and $\Sigma(1430)$ in the $J/\psi \to \Lambda \pi \bar{\Sigma}$ reaction

We study the $J/\psi \to \Lambda \pi \bar{\Sigma}$ reaction by looking at the $\pi^+ \Lambda$ mass distribution at low energies, in search of signals for the low lying $\Sigma^+$ states. Apart from a clear signal of the $\Sigma(1385) (3/2^+)$ state, we find a smaller peak for the predicted $\Sigma(1430) (1/2^-)$, which has already been confirmed by the Belle Collaboration. A first analysis, considering only the $\pi\Lambda$ interaction, shows that the low energy part of the spectrum is better reproduced including contributions from the $\Sigma(1430)$ and the predicted $\Sigma(1380)(1/2^-)$ state that has been claimed before from analyses of different experiments. However, when we consider the $\pi\bar{\Sigma}$ interaction the need for the $\Sigma(1380)$ disappears.

hep-ph↗

arXiv2026

Unveiling the elusive $\Sigma(1380)$ resonance through coupled-channel dynamics in $\Lambda_c^+\to\eta\pi^+\Lambda$ reaction

We investigate the $\Lambda_c^+ \to \eta \pi^+ \Lambda$ decay measured by the Belle and BESIII Collaborations, focusing on the possible role of the $\Sigma(1380)$ state with spin-parity $J^P=1/2^-$. In our theoretical framework, the $\Lambda(1670)$ and $a_0(980)$ are dynamically generated from meson-baryon and meson-meson final-state interactions, respectively, and the corresponding line shapes of these two states used here are applicable to all relevant hadronic reactions. Furthermore, the contributions from the intermediate $\Sigma(1385)$ resonance and the possible $\Sigma(1380)$ state are included explicitly. By comparing the invariant mass and angular distributions obtained with and without the $\Sigma(1380)$ state, we demonstrate that this state plays an important role in improving the description of the experimental data. We also identify the kinematic regions most sensitive to the possible $\Sigma(1380)$ contribution. Future high-precision measurements of this process will be instrumental for testing the existence of the $\Sigma$ state with $J^P=1/2^-$.

hep-ph↗

arXiv2026

Token-Level Policy Optimization: Linking Group-Level Rewards to Token-Level Aggregation via Sequence-Level Likelihood

Group Relative Policy Optimization (GRPO) has significantly advanced the reasoning ability of large language models (LLMs), particularly in their mathemat ical reasoning performance. However, GRPO and related entropy regularization methods still struggle with token-level sparse-rewards, which is an inherent chal lenge in chain-of-thought (CoT) reasoning. These approaches often rely on undifferen tiated token-level entropy regularization, which easily leads to entropy collapse or model degradation under sparse token rewards. In this work, we propose TEPO, a novel token-level framework that (1) leverages sequence-level likelihood to link group-level rewards with individual tokens via token-level aggregation, and (2) introduces a token-level KL-Divergence mask constraint that targets tokens with positive advantages and decreasing entropy to mitigate abrupt policy updates. Experiments demonstrate that TEPO not only achieves state-of-the-art performance on mathematical reasoning benchmarks but also markedly enhances training stability, reducing convergence time by 50% compared with GRPO/DAPO.

cs.CL↗

arXiv2026

Probing the isospin structure and low-lying resonances in $\Lambda_c^+ \to n\bar{K}^0 \pi^+$ decays

The Cabibbo-favored decay $\Lambda_c^+ \to n \bar{K}^0\pi^+$ offers a unique window to explore unresolved puzzles in the low-energy baryon spectroscopy and the isospin dynamics of the $\bar{K}N$ system. Recent experimental results present a, for now, contradiction: LHCb and Belle analyses of $\Lambda_c^+ \to p K^-\pi^+$ suggest the $pK^-$ ($I=0$) component dominates, while the Beijing Spectrometer III (BESIII) hints at significant contributions from both isospin $0$ and $1$ in the $n\bar{K}^0$ system of $\Lambda_c^+ \to n K_S^0 \pi^+$. Furthermore, the measured branching fraction of $\Lambda_c^+ \to n K_S^0 \pi^+$ exceeds SU(3) symmetry predictions by a factor of 3-4, signaling strong contributions from low-lying resonances. In this work, we provide a theoretical analysis of $\Lambda_c^+ \to n \bar{K}^0\pi^+$ within the coupled-channel chiral unitary approach, where the $N(1535)$ and $\Lambda(1670)$ can be dynamically generated. Our calculations show a narrow peak from $N(1535)$ in the $\pi^+ n$ invariant mass spectrum and a distinct dip from $\Lambda(1670)$ in the $\bar{K}^0 n$ spectrum. The dip structure is qualitatively consistent with the $\Lambda(1670)$ manifestation in $\bar{K}N \to \bar{K}N$ scattering, supporting its molecular interpretation. This study not only connects the experimental observations but also highlights $\Lambda_c^+ \to n \bar{K}^0\pi^+$ as a crucial process to disentangle the nature of $N(1535)$ and $\Lambda(1670)$. Future precise measurements of this decay channel by the BESIII, Belle II, LHCb, and the proposed Super Tau-Charm Factory are strongly encouraged.

hep-ph↗

arXiv2026

The dynamically generated $N(1535)$ state in the $\Lambda_c^+ \to p\bar{K}^0 \pi^0$ decay

We present a theoretical analysis of the process $\Lambda_c^+ \to p\bar{K}^0 \pi^0$ within the chiral unitary approach, with particular emphasis on the dynamically generated $N(1535)$ resonance. In addition to $N(1535)$, our model incorporates contributions from other intermediate resonances including $N(1650)$, $K^*(892)$, $K_0^*(1430)$, $N(1440)$, and $\Sigma(1750)$. The calculated invariant mass distributions and Dalitz plot are in good agreement with the recent Belle measurements. Our analysis highlights the crucial role of $N(1535)$ state in this decay channel and supports its interpretation as a dynamically generated state arising from coupled-channel meson-baryon interactions.

hep-ph↗

arXiv2026

Search for the low-lying excited baryon $\Sigma^*(1/2^-)$ through process $\Lambda^+_c \to \Lambda K^0 \pi^+$

Motivated by recent BESIII measurements of the singly Cabibbo-suppressed processes $\Lambda^+_c \to \Lambda K^+ \pi^0$ and $\Lambda^+_c \to \Lambda K_S^0 \pi^+$, we investigate the process $\Lambda^+_c \to \Lambda K^0 \pi^+$ by taking into account the contribution from the low-lying excited baryon $\Sigma^*(1/2^-)$, dynamically generated via the $S$-wave pseudoscalar meson-octet baryon interaction, as well as from the intermediate resonances $K^*(892)$ and $N(1535)$. Our model successfully reproduces the BESIII $\pi^+K^0$ invariant mass distribution, and predicts a distinct cusp structure around 1.43~GeV in the $\pi^+\Lambda$ invariant mass distribution, which is associated with the predicted $\Sigma^*(1/2^-)$. Future high-precise measurements of this process at BESIII, Belle~II, and the proposed Super Tau-Charm Facility experiments will be crucial for testing the existence of $\Sigma^*(1/2^-)$ and advancing our understanding of the light baryon spectrum.

hep-ph↗

arXiv2026

Role of $\Sigma(1660)$ in the $K^- p \to\pi^0\pi^0\Sigma^0$ reaction

The processes of $K^-p \to \pi^0 \pi^0 \Sigma^0$ and $K^- p \to \pi^0 \Lambda(1405)$ are studied within the effective Lagrangian approach. In addition to the ``background" contribution from the $u$-channel nucleon pole term, contribution from the $\Sigma(1660)$ resonance with spin-parity $J^P=1/2^+$ is also considered. For the $K^-p \to \pi^0 \pi^0 \Sigma^0$ reaction, we perform a calculation for the total and differential cross sections by considering the contribution from the $\Sigma(1660)$ intermediate resonance decaying into $\pi^0 \Lambda(1405)$ with $\Lambda(1405)$ decaying into $\pi^0 \Sigma^0$. With our model parameters, the available experimental data on both the $K^-p \to \pi^0 \pi^0 \Sigma^0$ and $K^- p \to \pi^0 \Lambda(1405)$ reactions can be fairly well reproduced. It is shown that we really need the contribution from the $\Sigma(1660)$ resonance, and that these experimental measurements could be used to determine some properties of the $\Sigma(1660)$ resonance.

hep-ph↗

arXiv2026

Finding a clean process $B^- \to K^- D^0 K^0$ to probe absolutely exotic four-quark states

Motivated by the observations of $T_{c\bar{s}0}(2900)^0$ and $T_{c\bar{s}0}(2900)^{++}$, we propose to search for $\tcsbar^0$ in the cleaner process $B^- \to K^- D^0 K^0$. In the $D^*K^*$ molecular picture, our estimates suggest that $T_{c\bar{s}0}(2900)^0$ should contribute significantly to the $D^0 K^0$ invariant mass distribution in $B^- \to K^- D^0 K^0$, as reported by the Belle II Collaboration. The corresponding fit fraction is estimated to be $(9.72\pm 3.92)\%$ or $(7.09\pm 5.88)\%$ in different fitting schemes. Further precise measurements of this process at Belle II and LHCb could be helpful for clarifying the nature of $T_{c\bar{s}0}(2900)$.

hep-ph↗

arXiv2025

GeoBridge: A Semantic-Anchored Multi-View Foundation Model Bridging Images and Text for Geo-Localization

Cross-view geo-localization infers a location by retrieving geo-tagged reference images that visually correspond to a query image. However, the traditional satellite-centric paradigm limits robustness when high-resolution or up-to-date satellite imagery is unavailable. It further underexploits complementary cues across views (\eg, drone, satellite, and street) and modalities (\eg, language and image). To address these challenges, we propose GeoBridge, a novel model that performs bidirectional matching across views and supports language-to-image retrieval. Going beyond traditional satellite-centric formulations, GeoBridge builds on a novel semantic-anchor mechanism that bridges multi-view features through textual descriptions for robust, flexible localization. In support of this task, we construct GeoLoc, the first large-scale, cross-modal, and multi-view aligned dataset comprising over 50,000 pairs of drone, street-view panorama, and satellite images as well as their textual descriptions, collected from 36 countries, ensuring both geographic and semantic alignment. We performed broad evaluations across multiple tasks. Experiments confirm that GeoLoc pre-training markedly improves geo-location accuracy for GeoBridge while promoting cross-domain generalization and cross-modal knowledge transfer. Code, dataset, and pretrained models will be released at https://github.com/MiliLab/GeoBridge.

cs.CV↗

arXiv2025

Token-Level Policy Optimization: Linking Group-Level Rewards to Token-Level Aggregation via Markov Likelihood

Group Relative Policy Optimization (GRPO) has significantly advanced the reasoning ability of large language models (LLMs), particularly by boosting their mathematical performance. However, GRPO and related entropy-regularization methods still face challenges rooted in the sparse token rewards inherent to chain-of-thought (CoT). Current approaches often rely on undifferentiated token-level entropy adjustments, which frequently lead to entropy collapse or model collapse. In this work, we propose TEPO, a novel token-level framework that incorporates Markov Likelihood (sequence likelihood) links group-level rewards with tokens via token-level aggregation. Experiments show that TEPO consistently outperforms existing baselines across key metrics (including @k and accuracy). It not only sets a new state of the art on mathematical reasoning tasks but also significantly enhances training stability.

cs.CL↗

arXiv2025

Role of $K^*_0(700)$ exchange in the $p \bar{p} \to \Lambda \bar{\Lambda}$ reaction

Based on the effective Lagrangian approach, we investigate the $p \bar{p} \to \Lambda \bar{\Lambda}$ reaction. Within this framework, we provide a dynamical explanation by analyzing its total and differential cross sections, as well as the polarization of the produced $\Lambda$ hyperon. Incorporating the $t$-channel exchange of the scalar $K^*_0(700)$ and pseudoscalar $K$ mesons, complemented by an $s$-channel contribution from the vector excited state, we can reproduce the current experimental data fairly well in a wide energy region. Compared to the conventional $K$ and $K^*(892)$ mesons exchange, the $K^*_0(700)$ meson exchange plays a more essential role in simultaneously capturing the observed features of the total and differential cross sections. The introduction of the vector $s$-channel resonance improves the description of the spin observables. This work gives a perspective to inspect the role of $K^*_0(700)$ and serves as a test to search for the resonances in the reaction $p \bar{p} \to \Lambda \bar{\Lambda}$ at threshold.

hep-ph↗

arXiv2025

Hadronic decay $D^+\to\pi^+\eta\eta$ and the $a_0(980)$ and $f_0(1370)$ contributions

Motivated by the resent BESIII Collaboration measurements of the process $D^+\to\pi^+\eta\eta$, we investigate this process by considering the contribution from the resonance $a_0(980)$, which is generated by $S$-wave pseudoscalar meson-pseudoscalar meson interaction, and the contribution from the intermediate scalar meson $f_0(1370)$. Our results could give a good description of the $\pi^+\eta$ and $\eta\eta$ invariant mass distributions, which implies that the contribution from the intermediate $f_0(1370)$, neglected in BESIII analysis, could play a role in this process. Furthermore, the predicted Dalitz plots are also consistent with the BESIII measurements. The more precise measurements about this process in future could shed light on the mechanism of this process and the properties of $f_0(1370)$ and $a_0(980)$.

hep-ph↗

arXiv2025

Roles of $a_0(980)$ and $a_0(1710)$ in Cabibbo-suppressed process $D^+\to \pi^0\pi^+\eta $

Motivated by the BESIII amplitude analysis of the single Cabibbo-suppressed process $D^+\to \pi^0\pi^+\eta$, we investigate this reaction by taking into account the contributions from the $a_0(980)$, $\rho$, and $a_0(1710)$, where the scalar meson $a_0(980)$ could be dynamically generated from the $S$-wave pseudoscalar meson-pseudoscalar meson interaction within the chiral unitary approach. Our theoretical predictions for the $\pi^0\eta$, $\pi^+\eta$, and $\pi^+\pi^0$ invariant mass distributions are in agreement with the BESIII measurements, especially the clear peaks around 1~GeV in the $\pi^0\eta$ and $\pi^+\eta$ invariant mass distributions could be associated with the dynamically generated state $a_0(980)$. Furthermore, we demonstrate that the intermediate $a_0(1710)$ is also necessary to describe the enhancement structure around $1.6\sim 1.7$~GeV in the $\pi^{0/+}\eta$ invariant mass distribution. More precise experimental measurements of this process could provide deeper insights into the nature of the scalar mesons $a_0(980)$ and $a_0(1710)$.

hep-ph↗

arXiv2025

Revisiting the $\Lambda_c^+\to \Lambda \eta \pi^+$ and the roles of intermediate resonances

In this paper, we first review the theoretical and experimental studies of the process $\Lambda_c^+ \to \pi^+ \eta \Lambda$. Motivated by the recent BESIII and Belle measurements, we have conducted a theoretical study of the process $\Lambda_c^+ \to \pi^+ \eta \Lambda$, where the $a_0(980)$ and $\Lambda(1670)$ resonances are dynamically generated from the $S$-wave meson meson and meson baryon interaction, respectively. Our results give a reasonable description of the invariant mass distributions, which implies that the spin flip contribution in the $\Sigma(1385)$ excitation plays an important role.

hep-ph↗

arXiv2025

Symbolic Foundation Regressor on Complex Networks

In science, we are interested not only in forecasting but also in understanding how predictions are made, specifically what the interpretable underlying model looks like. Data-driven machine learning technology can significantly streamline the complex and time-consuming traditional manual process of discovering scientific laws, helping us gain insights into fundamental issues in modern science. In this work, we introduce a pre-trained symbolic foundation regressor that can effectively compress complex data with numerous interacting variables while producing interpretable physical representations. Our model has been rigorously tested on non-network symbolic regression, symbolic regression on complex networks, and the inference of network dynamics across various domains, including physics, biochemistry, ecology, and epidemiology. The results indicate a remarkable improvement in equation inference efficiency, being three times more effective than baseline approaches while maintaining accurate predictions. Furthermore, we apply our model to uncover more intuitive laws of interaction transmission from global epidemic outbreak data, achieving optimal data fitting. This model extends the application boundary of pre-trained symbolic regression models to complex networks, and we believe it provides a foundational solution for revealing the hidden mechanisms behind changes in complex phenomena, enhancing interpretability, and inspiring further scientific discoveries.

cs.SC↗

arXiv2025

The $B^-\to J/\psi\eta^\prime K^-$ reaction and the $Y(4710)$ and $K_0^*(1430)$ contributions

Motivated by the recent LHCb Collaboration analysis, we have investigated the process $B^-\to J/\psi\eta^\prime K^-$ by considering the contributions from the resonances $Y(4710)$ and $K_0^*(1430)$. Our results are in good agreement with the measured invariant mass distributions and the Dalitz plot of LHCb, which supports the existence of the $K_0^*(1430)$ and the $Y(4710)$ in the process $B^-\to J/\psi\eta^\prime K^-$. Since the decay mode of $Y(4710)\to J/\psi \eta'$ is Okubo-Zweig-Iizuka (OZI) suppressed for the charmonium state, the measurements of the $\mathcal{B}(Y(4710)\to J/\psi\eta')$ through the process $B^-\to J/\psi \eta' K^-$ or other processes is helpful to understanding the nature of the $Y(4710)$. Thus, we advocate that Belle~II and LHCb Collaborations could perform the more precise analysis to confirm the evidence of the $Y(4710)$ state, which could be helpful to reduce the experimental uncertainties of its mass and width, and to explore its nature.

hep-ph↗

arXiv2025

Roles of $\Delta(1232)$, $N^(1520)$, and $N^(1650)$ resonances in $\gamma p\to \pi^0 \pi^0 p$ reaction within an effective Lagrangian approach

Roles of the $\Delta (1232)$, ${N}^{*}(1520)$, and ${N}^{*}(1650)$ resonances in the $\gamma p\to{\pi }^{0}{\pi }^{0}p $ reaction near threshold is investigated within an effective Lagrangian approach. We have calculated the differential cross sections of the $\gamma p\to{\pi }^{0}{\pi }^{0}p$ reaction by including the contributions from the $\Delta (1232)$, ${N}^{*}(1520)$, and ${N}^{*}(1650)$ intermediate states decaying into $\pi^0 p$ via the $s$-channel nucleon pole and $t$-channel $\rho$ exchange, and found that the current experimental measurements can be well reproduced. The production of $\Delta(1232)$ is mainly from the mechanism of the $s$-channel nucleon pole, while the ${N}^{*}(1520)$ and ${N}^{*}(1650)$ are produced from the mechanism of the $t$-channel $\rho$ exchange. It is expected that more experimental data on the $\gamma p \to \pi^0 \pi^0 p$ reaction can be used to explore the properties of the low-lying excited baryon states and also the scalar $f_0(500)$ and $f_0(980)$ mesons.

hep-ph↗