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.

China

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)

We have performed an updated analysis of the angular distribution of the $ \psi(3686) \to p\bar{p} $ decay by considering transverse beam polarization to investigate potential sources of forward-backward asymmetry and azimuthal modulation beyond the simple $ 1+\alpha\cos^2\theta $ form. We focus on the interference between the $ \psi(3686) $ resonance and two-photon exchange continuum process, as well as on the background from initial-state–final-state radiation (ISR–FSR) interference. A maximum-likelihood fit to the $ \cos\theta $ distribution of $ \psi(3686)\to p\bar{p} $ yields $ \alpha = 1.00 \pm 0.03 $ , which is consistent with previous results. Our model predicts a significant $ \sin(2\phi) $ modulation in the azimuthal angle, indicating the influence of transverse beam polarization. Based on these findings, two-dimensional angular analyses can be conducted in the future to fully disentangle the polarization and interference dynamics in charmonium decays to baryon pairs.

Zhi Gao

Rong-Gang Ping

Minggang Zhao

Update analysis of $ {\psi(3686)\to p\bar{p}}$ * The work is partly supported by the National Natural Science Foundation of China(NSFC) (12575112)

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.

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 have performed a next-to-leading-order (NLO) QCD sum rules analysis of the $1^{-+}$ light tetraquark states. By investigating various compact and molecular tetraquark currents, we extracted the mass spectra of the corresponding states, all of which lie above $1.7\,\text{GeV}$ . We have identified multiple $1^{-+}$ states around $2.0\,\text{GeV}$ matching well with $\pi_{1}(2015)$ , confirming that $\pi_{1}(2015)$ is an excellent tetraquark candidate. By contrast, our calculations exclude the possibility that the $\pi_{1}(1400)$ is a tetraquark or hybrid–tetraquark mixture. This result suggests that it may not exist, which is consistent with recent experimental results.

Wei-Yang Lai

Hong-Ying Jin

NLO QCD sum rules analysis of 1$^{− +}$ tetraquark states

The paper is devoted to the three-loop renormalization of the effective action for a two-dimensional non-linear sigma model using the background field method and a cutoff regularization in the coordinate representation. The coefficients of the renormalization constant and the necessary auxiliary vertices are found, as well as the asymptotic expansions of all three-loop diagrams, and their dependence on the type of regularizing function. A comparison is also made with the standard case of cutoff in the momentum representation.

Russia

P. Akacevich

A. Ivanov

I. Korenev

Three-loop singularity structure for a non-linear sigma model

We develop a rigid $$\mathcal {N}=(1,1)$$ superspace framework for spatially inhomogeneous impurity deformations in $$D=1+1$$ dimensions by embedding the impurity profile into a real background superfield (spurion). This spurionic completion provides a manifestly supersymmetric description at the level of the action and offers a systematic route to identify which inhomogeneous backgrounds preserve a nontrivial subset of supercharges. Focusing on static interface-type configurations, we determine the half-BPS condition on the spurion background and the corresponding supersymmetry projector. In the resulting half-BPS sector we derive the associated first-order BPS equation for static bosonic matter configurations and establish an exact Bogomol’nyi completion of the static energy, yielding a sharp bound saturated by BPS solutions. We further comment on how explicit coordinate dependence and derivative-dependent impurity couplings can obstruct the Bogomol’nyi structure, thereby motivating spurionic extensions that retain supersymmetric control over inhomogeneous deformations.

Brazil

D. Bazeia

A. Lehum

Half-BPS impurity backgrounds and supersymmetry

We extend a perturbative Dyson-type treatment and discrete-symmetry constraints from the Schrödinger and von Neumann equations to a dephasing Lindblad framework. This work develops further the odd-symmetric formulation involving dual temporal conditions from general dynamical considerations to specific tools of quantum mechanics. Applying the resulting scaling relations to published single- and double-diffractive data in $\textit{pp}$ and $$p\bar{p}$$ collisions (ISR, UA4, UA5, CDF, D0, ALICE, and E710), we show that single-diffraction cross sections are well described by a three-parameter fit with a relative RMS deviation of $$\sim 4\%,$$ substantially improving upon conventional approximations that neglect decoherence. The extracted decoherence factor is consistently $$\phi \approx 0.89,$$ in agreement across SD, DD, and E710-based (direct) estimates, and is naturally interpreted as $$\phi =1$$ for CP-invariant dephasing but $$\phi <1$$ for CPT-invariant dephasing, favouring the latter.

Australia

A. Klimenko

Decoherence, perturbations and symmetry in Lindblad dynamics: implications for diffractive dissociation

We present lattice results for $$f_K/f_{\pi }$$ in the iso-symmetric limit of pure QCD (isoQCD) with $$N_f=2+1$$ flavours, along with a determination of $$|V_{us}|/|V_{ud}|$$ and a study on the unitarity of the first row of the Cabibbo–Kobayashi–Maskawa (CKM) matrix after introducing strong isospin-breaking and QED effects. The results obtained are based on a combination of a Wilson unitary action and the mixed-action setup introduced in Bussone et al. (Hadronic physics from a Wilson fermion mixed-action approach: setup and scale setting. ; Eur Phys J C 84:506, 2024. ). The combination of the two regularisations enables a more precise control over the continuum-limit extrapolation.

Germany

Alessandro Conigli

Julien Frison

Spain

Alejandro Sáez

$$f_K/f_{\pi }$$ in iso-symmetric QCD and the CKM matrix unitarity

United Kingdom

Wen-Yuan Ai

Malcolm Fairbairn

Ken Mimasu

Tevong You

Erratum: Non-thermal production of heavy vector dark matter from relativistic bubble walls

In this work, we distinguish the isospin for the first time and study the diquark–diquark–antiquark type $$udsc\bar{c}$$ pentaquark states with zero isospin via the QCD sum rules systematically. We distinguish contributions of the pentaquark states with negative parity from positive parity unambiguously and obtain clean QCD sum rules for the pentaquark states with negative parity. Then we adopt the modified energy scale formula to choose the optimal energy scales of the QCD spectral densities, and obtain the mass spectrum of the $$udsc\bar{c}$$ pentaquark states with the quantum numbers $$I=0$$ and $$J^{P}={\frac{1}{2}}^-$$ , $${\frac{3}{2}}^-$$ , $${\frac{5}{2}}^-$$ , which could interpret the $$P_{cs}(4338)$$ and $$P_{cs}(4459)$$ in the $$J/\psi \Lambda $$ mass spectrum naturally.

Zhi-Gang Wang

Qi Xin

Analysis of the hidden-charm pentaquark candidates in the $$J/\psi \Lambda $$ mass spectrum via the QCD sum rules