In this work, we present a systematic study of the event characteristics and underlying physics relevant to neutrino-antineutrino discrimination in atmospheric neutrino charged-current interactions in large liquid scintillator detectors. This study encompasses the primary neutrino interactions, the subsequent secondary interactions of final-state particles, and the ensuing neutron captures. We investigate in detail the properties of final-state charged leptons and hadrons, deriving distinct distributions of inelasticity and neutron-capture multiplicity for both neutrino and antineutrino interactions. These distributions are used to quantify the performance of neutrino-antineutrino discrimination. Our findings lay the groundwork for atmospheric neutrino oscillation studies in large liquid scintillator detectors, particularly for determining the neutrino mass ordering.

China

Xinhai He

Gao-song Li

Yu-Feng Li

Wuming Luo

Liang-jian Wen

Atmospheric neutrino charged-current interactions at large liquid- scintillator detectors: I. physics of neutrino-antineutrino discrimination * Supported in part by the National Natural Science Foundation of China (12125506, 12075255), and the CAS Project for Young Scientists in Basic Research (YSBR-099)

In this work, we propose a method for quantifying the difference between nuclear parton distribution functions in different nuclei and parton distribution functions in free nucleons using relative entropy (also known as the Kullback-Leibler divergence), a measure widely employed in quantum information theory. By introducing certain constraints and the ''minimum relative entropy'' hypothesis, we can determine the shape of the structure function in the intermediate-$\textit{x}$ region, which is closely connected to the renowned EMC effect. For quark structure functions, our results are consistent with the latest global fits to experimental data. This agreement suggests that the relative entropy-based methodology may provide novel insights into nucleon structure, particularly in cases where experimental data and theoretical QCD constraints are limited, such as those relevant to gluon nPDFs. Therefore, we apply this methodology to gluon nPDFs, analyzing the results from two commonly used global fitting groups, EPPS21 and nNNPDF3.0. Our analysis suggests that the central values of EPPS21 align more closely with the ''minimum relative entropy'' hypothesis. This finding underscores the utility of the proposed method and provides a valuable reference for future global fits of nPDFs.

Shu-Man Hu

Ao-Sheng Xiong

Ji Xu

Fu-Sheng Yu

Ji-Xin Yu

An analysis of nuclear parton distribution function based on relative entropy * Supported in part by the National Natural Science Foundation of China (12335003), the Fundamental Research Funds for the Central Universities (lzujbky-2023-stlt01, lzujbky-2024-oy02, and lzujbky-2025-eyt01), and the Scientific Research Innovation Capability Support Project for Young Faculty (ZYGXQNJSKYCXNLZCXM-P2). Ji Xu is supported in part by the National Natural Science Foundation of China (12475098, 12105247)

We investigate the multipole structure of nucleon tensor form factors within the chiral quark-soliton model based on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>/</mo><msub><mi>N</mi><mi>c</mi></msub></math> expansion. Extending the previous leading-order analysis [N.-Y. Ghim et al., <a href="http://dx.doi.org/10.1103/PhysRevD.111.074024">Phys. Rev. D 111, 074024 (2025)</a>], we include the rotational <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>/</mo><msub><mi>N</mi><mi>c</mi></msub></math> corrections. These corrections provide the leading nonvanishing contributions to the flavor components that are absent at leading order, thereby completing the flavor decomposition of the tensor multipole form factors at the present order. We numerically evaluate the isoscalar tensor charge, the isovector anomalous tensor magnetic moment, and the isoscalar tensor quadrupole moment, obtaining <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>g</mi><mi>T</mi><mrow><mi>u</mi><mo>+</mo><mi>d</mi></mrow></msubsup><mo>=</mo><mn>0.81</mn></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>κ</mi><mi>T</mi><mrow><mi>u</mi><mo>−</mo><mi>d</mi></mrow></msubsup><mo>=</mo><mn>1.97</mn></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>E</mi><mi>T</mi><mrow><mi>u</mi><mo>+</mo><mi>d</mi></mrow></msubsup><mo stretchy="false">(</mo><mn>0</mn><mo stretchy="false">)</mo><mo>=</mo><mn>5.98</mn></math>, respectively. The isoscalar tensor charge and quadrupole moment are mainly governed by the valence-quark contribution, whereas the isovector anomalous tensor magnetic moment receives a sizable Dirac-sea contribution. We also examine the momentum-transfer dependence of the corresponding form factors. They decrease monotonically with increasing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><mi>t</mi></math>. In particular, the isovector anomalous tensor magnetic form factor shows a pronounced falloff in the small-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>t</mi><mo stretchy="false">|</mo></math> region, reflecting the importance of the Dirac sea in the tensor dipole structure.

South Korea

Nam-Yong Ghim

France

Ho-Yeon Won

June-Young Kim

Hyun-Chul Kim

Multipole structure of nucleon tensor form factors

Hadron-hadron interactions, being nonperturbative in nature, play a significant role in addressing phenomenological questions in particle physics. Femtoscopy is a powerful tool in heavy-ion collision experiments, enabling the extraction of hadron-hadron interactions via momentum-correlation functions (CFs). These CFs are typically expressed as a convolution of source functions and hadron-hadron wave functions, with the latter encoding information about the interactions. However, source functions remain poorly constrained and are commonly approximated by a Gaussian form. Reconstructing source functions from experimental correlation data constitutes an 'inverse problem.' To address this, we propose a toy model based on Tikhonov regularization. Using a square-well potential with four distinct strengths, we calculate the CFs for inputs of single Gaussian source functions and mixed Gaussian source functions. The resulting CFs are then used to reconstruct the source functions via Tikhonov regularization. Our results show that the Gaussian source function can be successfully reconstructed, highlighting the potential of this approach for extracting realistic source functions from hadron pairs of interest.

Qi-Wei Yuan

Ming-Zhu Liu

Zhi-Wei Liu

Li-Sheng Geng

Solving the inverse source problem in femtoscopy with a toy model * Supported in part by the Fundamental and Interdisciplinary Disciplines Breakthrough Plan of the Ministry of Education of China (JYB2025XDXM204) and the National Natural Science Foundation of China (W2543006, 12435007). Ming-Zhu Liu acknowledges support from the National Natural Science Foundation of China (12575086). Zhi-Wei Liu acknowledges support from the National Natural Science Foundation of China (12405133) and from the Shenzhen Science and Technology Program (ZDSYS20230626091501002). Fu-Sheng Yu and Ao-Sheng Xiong acknowledge support from the Scientific Research Innovation Capability Support Project for Young Faculty (ZYGXQNJSKYCXNLZCXM-P2) and from the Fundamental Research Funds for the Central Universities (lzujbky-2023-stlt01, lzujbky-2024-oy02, lzujbky-2025-eyt01)

The tensor-polarized parton density is defined by the forward matrix element of a partonic operator in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi><mo stretchy="false">→</mo><mi mathvariant="normal">Δ</mi></math> transition. In this work, we investigate it by employing the large-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>c</mi></msub></math> light-cone wave function derived from the mean-field approach. The mean-field picture is based on low-energy effective dynamics in the large-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>c</mi></msub></math> limit, where the baryon wave function is formulated in the rest frame. By exploiting the covariance of the mean-field solution, we derive the corresponding large-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>c</mi></msub></math> light-cone wave function—decomposed unambiguously into <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mi>Q</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>Q</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>7</mn><mi>Q</mi></math>, and higher Fock components—in the infinite momentum frame. Evaluating the overlap of these wave functions, we derive an overlap representation of the tensor-polarized parton density in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi><mo stretchy="false">→</mo><mi mathvariant="normal">Δ</mi></math> transition and find that the leading contribution arises from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>Q</mi></math> Fock sector. This indicates that the tensor-polarized parton density directly probes the genuine <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>Q</mi></math> component and is governed by chiral dynamics. Our numerical analysis shows that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi><mo stretchy="false">→</mo><mi mathvariant="normal">Δ</mi></math> tensor-polarized parton density is suppressed, consistent with standard large-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>c</mi></msub></math> expectations. Finally, we establish connections among the tensor-polarized parton density, the generalized parton distribution <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>H</mi><mi>X</mi></msub></math>, and the energy-momentum tensor form factor <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>F</mi><mn>4</mn></msub></math>.

United States

Tensor-polarized parton density in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi><mo stretchy="false">→</mo><mi mathvariant="normal">Δ</mi></math> transition from the large-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>c</mi></msub></math> light-cone wave function

We evaluate discovery prospects for photophobic axion-like particles (ALPs) in the $\textit{WWjj}$ final state at the High-Luminosity LHC (HL-LHC; $\sqrt{s}=14\ {\rm{TeV}}$ , ${\cal{L}}=3\ {\rm{ab}}^{-1}$ ). In the photophobic limit ( $g_{a\gamma\gamma}=0$ ), ALPs couple to electroweak gauge bosons and are produced in association with two jets ( $ pp\to jj\ a $ ) via both $\textit{s}$-channel electroweak exchange and vector boson fusion (VBF)–like topologies, followed by $a\to W^+W^-$ decay. We target the different-flavour dilepton mode $W^+W^- \to e^\pm\mu^\mp\nu \bar{\nu}$ with two jets and moderate missing transverse momentum. The analysis employs a two-step strategy: initial preselection that defines the signal-like final state, followed by a multivariate analysis (MVA) trained on dijet and dileptonic-$\textit{WW}$ kinematics from both the $\textit{s}$-channel and VBF-like production mechanisms to separate signal from background; the MVA threshold is optimized independently at each $m_a$ . We present 2$\textit{σ}$ and 5$\textit{σ}$ discovery sensitivities for the ALP–$\textit{W}$ coupling $g_{aWW}$ across the 170–4000 GeV mass range. For $260\ {\rm{GeV}}\le m_a\le1500\ {\rm{GeV}}$ , the 2$\textit{σ}$ (5$\textit{σ}$) sensitivity is approximately flat around $ 0.61(0.76)\ {\rm{TeV}}^{-1}$ . At large masses/couplings, the mapping between an experimental rate and a single EFT parameter $g_{aWW}$ can become UV sensitive, and we treat the extreme high-mass/high-coupling corner as an extrapolation; therefore, we also report model-independent discovery thresholds for the fiducial quantity $ \sigma(pp\to jj\ a)\times\rm{Br}(a\to W^+W^-) $ over the same mass range to enable reinterpretation for other models. These results indicate that the $WWjj$ topology offers competitive and complementary sensitivity to heavy photophobic ALPs at the HL-LHC.

Jiaojiao Feng

Ying-nan Mao

Kechen Wang

Discovery prospects for photophobic axion-like particles in the $\textit{WWjj}$ final state at the High-Luminosity LHC * Jiaojiao Feng and Kechen Wang are supported by the National Natural Science Foundation of China (11905162), the Excellent Young Talents Program of the Wuhan University of Technology (40122102, 40122103) and the research program of the Wuhan University of Technology (2020IB024, 104972025KFYjc0101). Ying-nan Mao is supported by the National Natural Science Foundation of China (12205227). The simulation and analysis work of this article was completed with the computational cluster provided by the Theoretical Physics Group at the Department of Physics, School of Physics and Mechanics, Wuhan University of Technology

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 $\textit{u}$-channel nucleon pole term, the 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 the contribution from the $ \Sigma(1660) $ resonance is necessary, and that these experimental measurements could be used to determine some properties of the $ \Sigma(1660) $ resonance.

Xing-Yi Ji

Si-Wei Liu

Wen-Tao Lyu

De-Min Li

En Wang

Ju-Jun Xie

Role of Σ(1660) in the $\textit{K}$ $^{−}$ $\textit{p}$ → $\textit{π}$ $^{0}$ $\textit{π}$ $^{0}$Σ$^{0}$ reaction * Supported by the National Key R&D Program of China (2023YFA1606703, 2024YFE0105200), the National Natural Science Foundation of China (12435007, 12475086, 12192263, 12361141819, 1252200936), the Natural Science Foundation of Henan (232300421140, 252300423951) and the Zhengzhou University Young Student Basic Research Projects (PhD students) (ZDBJ202522)

In this study, we investigate the possibility of enhancing the di-jet resonance searches by tagging the final state radiation (FSR) jet using an event-level deep neural network. It is found that solely relying on the 4-momenta of the leading three jets allows the algorithm to achieve good discriminating power that can identify the hardest FSR jet in the signal while rejecting other soft jets. Once the invariant mass is corrected with the tagged FSR jet, the mass resolution of the signal is greatly enhanced, and the sensitivity of the search is also improved by more than 10%. By crafting the input variables carefully, the algorithm introduces minimal mass sculpting for the background, and its applicability extends to a broad mass range. This work proves that FSR jet tagging can potentially enhance di-jet resonance searches, suiting various stages of the physics programmes at the Large Hadron Collider (LHC) and High-Luminosity LHC (HL-LHC).

Bingxuan Liu

Yuxuan Shen

Yuanshunzi Sui

Enhancing di-jet resonance searches via a final-state radiation jet tagging algorithm * Bingxuan Liu is supported by Shenzhen Campus of the Sun Yat-sen University under project 74140-12255011, and by the Young Scientists Fund (C Class) of the National Natural Science Foundation of China (12405122). Both Yuxuan Shen and Yuanshunzi Sui are supported by College Students’ Innovative Entrepreneurial Training Plan Program

The charmed baryon was first observed experimentally in 1975, one year after the charm quark's confirmation via the discovery of the $ J/\psi $ particle. Studying charmed baryon decays provides a pathway to investigate both strong and weak interactions, leveraging the weak decays of the embedded charm quark. However, for approximately three decades following its discovery, experimental knowledge of charmed baryons remained significantly limited compared to those of the hidden-charm $\textit{ψ}$ mesons and open-charm $ D_{(s)} $ mesons. This situation changed markedly starting in 2014, when dedicated data collection for charmed baryons commenced at BESIII. In this article, we review the experimental progress achieved since 2014 in understanding the weak decays of the charmed baryons.

Pei-Rong Li

Xiao-Rui Lyu

Yangheng Zheng

Experimental overview on the charmed baryon decays * The authors thank Fusheng Yu for useful discussions. The authors are supported in part by National Natural Science Foundation of China (12221005, 12422504); CAS Project for Young Scientists in Basic Research (YSBR-117); Fundamental Research Funds for the Central Universities, Lanzhou University (lzujbky-2025-ytB01, lzujbky-2023-stlt01, lzujbky-2023-it32), University of Chinese Academy of Sciences

We propose a novel method to detect reactor $ \overline{\nu}^{}_e \to \overline{\nu}^{}_\mu $ and $ \overline{\nu}^{}_e \to \overline{\nu}^{}_\tau $ oscillations by using elastic antineutrino-electron scattering processes $ \overline{\nu}^{}_\alpha + e^- \to \overline{\nu}^{}_\alpha + e^- $ (for $ \alpha = e, \mu, \tau $ ), among which the $ \overline{\nu}^{}_e $ events can be singled out by accurately measuring the $ \overline{\nu}^{}_e $ flux via the inverse beta decay $ \overline{\nu}^{}_e + p \to e^+ + n $ . A proof-of-concept study shows that such measurements will not only be able to test the conservation of probability for reactor antineutrino oscillations, but also offer a new possibility to probe leptonic CP violation at the one-loop level.

Yifang Wang

Zhi-zhong Xing

Shun Zhou

Towards a detection of reactor ${\overline {\boldsymbol v}_{\boldsymbol e} \boldsymbol\to \overline {\boldsymbol v}_{\boldsymbol\mu} }$ and ${\overline {\boldsymbol v}_{\boldsymbol e} \boldsymbol\to \overline {\boldsymbol v}_{\boldsymbol\tau} }$ oscillations with possible CP violation * Supported in part by the National Natural Science Foundation of China (12475113, 12535007), the CAS Project for Young Scientists in Basic Research (YSBR-099), and the Scientific and Technological Innovation Program of IHEP (E55457U2)