This study investigates the ultraviolet realization of semileptonic four-fermion operator $ O_{ledq}^{\alpha \beta 11} $ that incorporates Majorana dark matter (DM) in both lepton-flavor-conserving (LFC) and lepton-flavor-violating (LFV) scenarios at the one-loop level via box diagram, thereby effectively alleviating the lower bounds on the new physics scale. In addition, we investigate the interplay between model-independent constraints on the Wilson coefficients and DM direct detection, relic density, and collider searches in the context of fermion portal DM model with two mediators. We found that both the projected future constraint on the LFC Wilson coefficient $ C_{ledq}^{2211}/\Lambda^2 \lt $ $ (12.3\; \text{TeV})^{-2} $ from the measurements of neutrino non-standard interaction in the next-generation neutrino oscillation experiments, and the LFV constraint $ C_{ledq}^{1211}/\Lambda^2 \lt \left(2.2\times 10^3\; \text{TeV} \right)^{-2} $ from ongoing charged-lepton-flavor-violation searches, provide a complementary exploration of the parameter space encompassing the DM and scalar masses. With a colored mediator mass of approximately $ 2\; \text{TeV} $ , the sensitivity of the indirect constraints on the four-fermion operator can surpass those of collider searches and DM direct detection, in scenarios where the masses of the DM and scalar are close. By ensuring the correct DM relic density, however, we find that the collider searches and DM direct detection are more sensitive to the electroweak-scale DM and scalar than indirect constraints.

China

Yuxuan He

Gang Li

Jia Liu

Xiao-Ping Wang

Xiang Zhao

Lepton flavor of four-fermion operator and fermion portal dark matter * Gang Li and Xiang Zhao are supported by the National Natural Science Foundation of China (12347105, 12505127), the Guangdong Basic and Applied Basic Research Foundation (2024A1515012668). The work of Jia Liu is supported by the National Science Foundation of China (12235001, 12475103) and State Key Laboratory of Nuclear Physics and Technology (NPT2025ZX11). The work of Xiao-Ping Wang is supported by National Science Foundation of China (12375095) and the Fundamental Research Funds for the Central Universities

We propose to search for <math altimg='si25.svg'><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup></math> in the decay <math altimg='si26.svg'><mrow><msub><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle><mi>b</mi></msub><mo>&#8594;</mo><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup><msup><mi>D</mi><mo>&#8722;</mo></msup></mrow></math>, which serves as a tagged and reconstructible source of <math altimg='si25.svg'><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup></math>. A possible fully charged final state is <math altimg='si27.svg'><mrow><msub><mrow><mo>[</mo><msub><mrow><mo>(</mo><mi>p</mi><msup><mi>K</mi><mo>&#8722;</mo></msup><msup><mi>K</mi><mo>&#8722;</mo></msup><msup><mi>&#960;</mi><mo>+</mo></msup><mo>)</mo></mrow><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mi>c</mi><mn>0</mn></msubsup></msub><msup><mi>&#960;</mi><mo>+</mo></msup><mo>]</mo></mrow><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup></msub><mspace width='0.16em' /><msub><mrow><mo>(</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>&#960;</mi><mo>&#8722;</mo></msup><msup><mi>&#960;</mi><mo>&#8722;</mo></msup><mo>)</mo></mrow><msup><mi>D</mi><mo>&#8722;</mo></msup></msub></mrow></math>, where the subscripts indicate the parent hadron in the decay chain. We estimate the branching fraction to be <math altimg='si28.svg'><mrow><mi mathvariant='script'>B</mi><mrow><mo>(</mo><msub><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle><mi>b</mi></msub><mo>&#8594;</mo><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup><msup><mi>D</mi><mo>&#8722;</mo></msup><mo>)</mo></mrow><mo linebreak='goodbreak'>=</mo><mrow><mo>(</mo><mn>5.1</mn><mo>&#177;</mo><mn>3.9</mn><mo>)</mo></mrow><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>4</mn></mrow></msup></mrow></math>, while the fully charged final state corresponds to an effective branching fraction of order <math altimg='si29.svg'><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>8</mn></mrow></msup></math>. These results indicate that LHCb has the potential to discover <math altimg='si25.svg'><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup></math>. The prospects for observing <math altimg='si30.svg'><msubsup><mstyle mathvariant='normal'><mi>&#937;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup></math> are also briefly discussed.

Chao-Qiang Geng

Xiang-Nan Jin

Chia-Wei Liu

Xin-Yi Liu

Xiao Yu

Potential of discovering <math altimg='si25.svg'><msubsup><mstyle mathvariant='normal'><mi>&#926;</mi></mstyle><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup></math> in &#923; <inf><italic>b</italic></inf> decays

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

Electroweak (EW) amplitudes in the gauge-Goldstone five-component formalism have a distinctive property: gauge symmetry is imprinted in the amplitudes, manifested as the massive Ward identity (MWI) $ k^M{\cal{M}}_M=0 $ . In this study, we used the HELAS package to numerically study gauge symmetry in EW amplitudes. First, we directly tested gauge symmetry by examining the MWI of amplitudes. Second, we modified the couplings within a vertex and among vertices to check if and how the MWI changes. Third, we tested gauge symmetry by considering the couplings modified by operators from the standard model effective field theory (SMEFT). Similar to the standard model, there are relations between different couplings that are protected by gauge symmetry. We observed that, if we modify the couplings to deviate from the relations, the MWI is violated. In contrast, the MWI is restored when the relations between couplings reduce to those in the SMEFT.

Wang-Fa Li

Junmou Chen

Qian-Jiu Wang

Zhao-Huan Yu

Numerical study on the gauge symmetry of electroweak amplitudes * Junmou Chen is supported by National Natural Science Foundation of China (12205118), Wang-Fa Li, Qian-Jiu Wang, and Zhao-Huan Yu are supported by the Guangzhou Science and Technology Planning Project (2024A04J4026)

The high-density region of the QCD phase diagram displays an intricate competition between color superconductivity and the QCD Kondo effect due to color exchange in quark matter containing a single heavy quark impurity. We explore the characteristic impurity-induced superconducting subgap states arising in such systems by generalizing the surrogate model solver, recently considered in the context of condensed matter physics [<a href="http://dx.doi.org/10.1103/PhysRevB.108.L220506">Phys. Rev. B 108, L220506 (2023)</a>]. The method consists of approximating the full superconducting bulk by only a small number of effective levels whose parameters are chosen so as to best reproduce the Matsubara frequency dependence of the impurity-bulk hybridization function. We numerically solve a surrogate QCD Kondo model describing a quantum impurity color exchange coupled to a two-color two-flavor superconducting bulk. The results directly indicate the presence of multiple phase transitions as the coupling of the impurity to the bulk is increased, due to the interplay between various overscreened states. The methods introduced here are straightforward enough to be extended to more realistic QCD scenarios.

Romania

Virgil V. Baran

Denmark

Jens Paaske

Yu-Shiba-Rusinov states in color-superconducting quark matter

A future $ e^+e^- $ collider could run at the $\textit{Z}$-pole to perform important electroweak (EW) precision measurements, but such a run may not be viable for a future muon collider. However, this can be compensated for by measuring other EW processes utilizing the high energy and large luminosity of the muon collider. In this paper, we consider the measurements of the vector boson fusion processes of $ WW/WZ/W\gamma $ to a pair of fermions (along with a $ \nu_{\mu}\bar{\nu}_{\mu} $ or $ \nu_{\mu}\mu^+/\bar{\nu}_{\mu}\mu^- $ pair) at a high-energy muon collider and study their potential for probing EW observables. We consider two run scenarios for the muon collider with center-of-mass energies of 10 and 30 TeV, respectively, and focus on the processes involving $ f=b,c,\tau $ and the dimension-6 operators that directly modify the corresponding fermions coupling to the $ Z/W $ bosons. The invariant mass distribution of the $ f\bar{f} $ pair helps to separate the events from the $ Z/W $ and high-energy resonances, whereas the polar angle of the outing fermion provides additional information. Through a chi-squared analysis on the binned distributions and combining the information from the $\textit{WW}$ and $ WZ/W\gamma $ fusion processes, all relevant Wilson coefficients can be constrained simultaneously. The precision surpasses the current EW measurement constraints and is even competitive with future $ e^+e^- $ colliders. Our analysis can be included in a more complete framework that is required to fully determine the potential of muon colliders in EW precision measurements.

Hao-Qiao Li

Hai-Ning Yan

Jiayin Gu

Germany

Xiao-Ze Tan

Probing $\textit{Z}$/$\textit{W}$ pole physics at high-energy muon colliders via vector-boson-fusion processes * Supported by the National Natural Science Foundation of China (NSFC) (12035008, 12375091, 12347171), and the Innovation Program for Quantum Science and Technology (2024ZD0300101). Xiao-Ze Tan also acknowledges the support from Helmholtz – OCPC (Office of China Postdoctoral Council) Postdoctoral Fellowship Program

We study $ \cos2\phi $ azimuthal asymmetry in doubly longitudinally polarized proton-proton Drell-Yan collisions within the transverse momentum dependent factorization framework. The asymmetry arises from the convolution of the longitudinal transversity distribution $ h_{1L}^{\perp} $ for both protons. Using the Bacchetta-Delcarro-Pisano-Radici-Signori parameterization for the nonperturbative Sudakov form factor and the Wandzura-Wilczek approximation for collinear $ h_{1L}^{\perp} $ , we predict the double spin asymmetry $ A_{LL}^{\cos2\phi} $ at RHIC and NICA kinematics. Our results demonstrate sensitivity to sea quark distributions, with the asymmetry reaching up to 25% for maximal sea quark contributions. These predictions highlight the potential of polarized Drell-Yan measurements to probe sea quark dynamics and advance our understanding of nucleon structures.

Hui Li

Ting Hu

Liang-Liang Liu

Xiao-Yu Wang

Zhun Lu

Asymmetry ${{\boldsymbol A}_{\boldsymbol{LL}}^{\bf\cos2\boldsymbol\phi}} $ in the polarized proton-proton Drell-Yan process within TMD factorization * Hui Li is supported by Fundamental Research Program of Shanxi Province (202203021222224) and Natural Science Foundation of Shanxi Normal University (JCYJ2023021). Xiao-Yu Wang is supported by the Natural Science Foundation of Henan Province (242300421377, 232300421140)

We study the transverse momentum ( $p_T$ ) differential anisotropic flow and flow fluctuation in Pb+Pb collisions at $\sqrt{s_{_{NN}}}$ =5.02 TeV at the LHC. A (3+1)-dimensional CLVisc hydrodynamics framework with fluctuating TRENTO (or AMPT) initial conditions is utilized to simulate the space-time evolution of the quark-gluon plasma (QGP) medium. The effects of shear viscosity and the sub-nucleon structure on anisotropic flow and flow fluctuation are analyzed. Our result shows that shear viscosity tends to suppress both flow coefficients ( ${v_2\{2}\}$ , ${v_2\{4\}}$ , and ${\langle v_2\rangle}$ ) and flow fluctuation ( ${\sigma_{v_2}}$ ) owing to its smearing effect on local density fluctuation. The flow coefficients appear to be insensitive to the sub-nucleon structure, whereas the flow fluctuation ${\sigma_{v_2}}$ tends to be suppressed by the sub-nucleon structure in central collisions but enhanced in peripheral collisions. After taking into account the sub-nucleon structure effect, our numerical result can qualitatively describe the relative flow fluctuations ( ${v_2\{4\}/v_2\{2\}}$ , $F({v_2})$ ) measured by the ALICE Collaboration at the LHC. We further investigate the effects of shear viscosity, sub-nucleon structure, and initial condition model on the flow angle and flow magnitude decorrelations ( ${A_2^f}$ , ${M_2^f}$ ) using the four-particle correlation method. We find that the flow decorrelation effect is typically stronger in central collisions than in peripheral collisions. The flow angle decorrelation is found to be insensitive to the shear viscosity and sub-nucleon structure, whereas the flow magnitude decorrelation shows quite different behaviors when using the TRENTO and AMPT initial condition models. Our study sheds light on the anisotropic flow, transport properties, and initial structure of the QGP created in high-energy nuclear collisions.

Jie Zhu

Canada

Xiang-Yu Wu

Guang-You Qin

Anisotropic flow, flow fluctuation, and flow decorrelation in relativistic heavy-ion collisions: the roles of sub-nucleon structure and shear viscosity * Supported in part by the Natural Science Foundation of China (12225503, 11890710, 11890711, 11935007). Zhu Jie is supported in part by the China Scholarship Council (202306770009). Wu Xiang-Yu is supported in part by the National Science Foundation within the framework of the JETSCAPE collaboration (OAC-2004571) and in part by the Natural Sciences and Engineering Research Council of Canada. Some of the calculations were performed in the Nuclear Science Computing Center at Central China Normal University (NSC$^{3}$), Wuhan, Hubei, China.

We search for nuclear recoil signals of dark matter (DM) models with a light mediator using data taken from a p-type point-contact germanium detector of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90% confidence level upper limits on the DM-nucleon interaction cross section from 205.4 kg-day exposure data are derived, excluding the new parameter space in 2−3 GeV DM mass when the mediator mass is comparable to or lower than the typical momentum transfer. We further interpret our results to constrain a specific self-interacting DM model with a light mediator coupling to the photon through kinetic mixing and set experimental limits on the model parameter region favored by astrophysical observations.

Qi-Yuan Nie

Wen-Han Dai

Hao Ma

Qian Yue

Ke-Jun Kang

Yuan-Jing Li

Hai-Peng An

C. Greeshma

Jian-Ping Chang

Yun-Hua Chen

Jian-Ping Cheng

Zhi Deng

Chang-Hao Fang

Xin-Ping Geng

Hui Gong

Tao Guo

Xu-Yuan Guo

Li He

Jin-Rong He

Han-Xiong Huang

Tu-Chen Huang

S. Karmakar

Jian-Min Li

Jin Li

Yu-Lan Li

Hau-Bin Li

Ming-Chuan Li

Han-Yu Li

Qian-Yun Li

Ren-Ming-Jie Li

Xue-Qian Li

Yi-Fan Liang

Bin Liao

Fong-Kay Lin

Shin-Ted Lin

Jia-Xuan Liu

Yan-Dong Liu

Yuan-Yuan Liu

Shu-Kui Liu

Yu Liu

Hui Pan

Ning-Chun Qi

Jie Ren

Xi-Chao Ruan

Man-Bin Shen

Manoj Kumar Singh

Wen-Liang Sun

Tian-Xi Sun

Chang-Jian Tang

Yang Tian

Hong-Fei Wan

Jun-Zheng Wang

Yu-Feng Wang

Guang-Fu Wang

Li Wang

Qing Wang

Henry-Tsz-King Wong

Yu-Cheng Wu

Hao-Yang Xing

Kai-Zhi Xiong

Rui Xu

Yin Xu

Tao Xue

Yu-Lu Yan

Li-Tao Yang

Nan Yi

Chun-Xu Yu

Hai-Jun Yu

Ming Zeng

Zhi Zeng

Zhen-Hua Zhang

Zhen-Yu Zhang

Peng Zhang

Feng-Shou Zhang

Lei Zhang

Ji-Zhong Zhao

Kang-Kang Zhao

Ming-Gang Zhao

Ji-Fang Zhou

Zu-Ying Zhou

Jing-Jun Zhu

 (CDEX Collaboration)

Constraining dark matter models with a light mediator from the CDEX-10 experiment at China Jinping Underground Laboratory * Supported by the National Key Research and Development Program of China (2023YFA1607101) and the National Natural Science Foundation of China (12425507, 12322511, 12175112)

Our study focuses on the weak decay of <math><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>→</mo><mi>p</mi><mover><mi>n</mi><mo>¯</mo></mover></math>, which is the only possible two-body baryonic decay in the <math><mi>D</mi></math> meson system. An analysis using perturbative quantum chromodynamics (pQCD) is challenging in this decay due to the small amount of energy released. In particular, naive factorization, suppressed by the light quark masses, results in a minor contribution to this channel. In the framework of final state interactions, the hidden strangeness in the intermediate state naturally avoids this chiral suppression from light quark masses. The branching fraction is predicted to be <math><mi>B</mi><mo>(</mo><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>→</mo><mi>p</mi><mover><mi>n</mi><mo>¯</mo></mover><mo>)</mo><mo>=</mo><mo>(</mo><mn>1.43</mn><mo>±</mo><mn>0.10</mn><mo>)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></math>, in agreement with the experimental value of <math><mo>(</mo><mn>1.22</mn><mo>±</mo><mn>0.11</mn><mo>)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></math>. We also analyze the decays of <math><mi>B</mi></math> mesons into two charmed baryons involving annihilation-type topological diagrams. In these decays, we conduct a joint analysis of naive factorization and final state interactions. Using the experimental upper bound of <math><mi>B</mi><mo>(</mo><msubsup><mi>B</mi><mi>s</mi><mn>0</mn></msubsup><mo>→</mo><msubsup><mi>Λ</mi><mi>c</mi><mo>+</mo></msubsup><msubsup><mover><mi>Λ</mi><mo>¯</mo></mover><mi>c</mi><mo>−</mo></msubsup><mo>)</mo><mo>&lt;</mo><mn>8</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>, we set a constraint on the coupling constant <math><msub><mi>g</mi><mrow><msup><mi>D</mi><mo>+</mo></msup><msubsup><mi>Λ</mi><mi>c</mi><mo>+</mo></msubsup><mi>n</mi></mrow></msub><mo>&lt;</mo><mn>7.5</mn></math>. Final state interactions lead to a prediction of the decay parameter <math><mi>γ</mi><mo>(</mo><msubsup><mi>B</mi><mi>s</mi><mn>0</mn></msubsup><mo>→</mo><msubsup><mi>Λ</mi><mi>c</mi><mo>+</mo></msubsup><msubsup><mover><mi>Λ</mi><mo>¯</mo></mover><mi>c</mi><mo>−</mo></msubsup><mo>)</mo><mo>&gt;</mo><mn>0.8</mn></math>, whereas pQCD predicts it to be negative. We propose future measurements of <math><msup><mi>B</mi><mn>0</mn></msup><mo>→</mo><msubsup><mi>Ξ</mi><mi>c</mi><mo>+</mo></msubsup><msubsup><mover><mi>Ξ</mi><mo>¯</mo></mover><mi>c</mi><mo>−</mo></msubsup></math>, predicting a significant <math><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><msub><mo>)</mo><mi>F</mi></msub></math> breaking effect with <math><mfrac><mrow><mi>B</mi><mo>(</mo><msup><mi>B</mi><mn>0</mn></msup><mo>→</mo><msubsup><mi>Ξ</mi><mi>c</mi><mo>+</mo></msubsup><msubsup><mover><mi>Ξ</mi><mo>¯</mo></mover><mi>c</mi><mo>−</mo></msubsup><mo>)</mo></mrow><mrow><mi>B</mi><mo>(</mo><msubsup><mi>B</mi><mi>s</mi><mn>0</mn></msubsup><mo>→</mo><msubsup><mi>Λ</mi><mi>c</mi><mo>+</mo></msubsup><msubsup><mover><mi>Λ</mi><mo>¯</mo></mover><mi>c</mi><mo>−</mo></msubsup><mo>)</mo></mrow></mfrac><mo>=</mo><mn>1.4</mn><mo>%</mo></math>, contrary to the naive estimate of 5.3%. We strongly recommend future measurements.

Hidden strangeness in meson weak decays to baryon pair