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

We have conducted an extensive study that highlights the potential of the Indian Coherent Neutrino-nucleus Scattering Experiment (ICNSE) detector in constraining neutrino-quark interactions that go beyond the standard model. By utilizing reactors with varied core configurations and power outputs as sources for electron antineutrinos, and operating with a target mass of 10 kg over a year, our findings reveal that the ICNSE detector is remarkably effective in narrowing down the vast majority of the Non-standard Interaction (NSI) parameter space. Moreover, incorporating results from two distinct detectors, like sapphire and high-purity germanium, markedly enhances sensitivity by reducing the degeneracies between some pairs of NSI parameters to a smaller region. This research highlights its role in enabling future developments and investigations.

India

S. Behera

S. Panda

D. Mishra

Study of the beyond standard model interaction using coherent elastic neutrino-nucleus scattering process

Open effective field theories provide a systematic framework for describing systems coupled to an environment, where dissipation, noise, and modified conservation laws naturally arise. Working within the Schwinger-Keldysh formalism, we examine open extensions of three well-studied theories: the superfluid, Maxwell theory, and Einstein gravity. In gauge and gravitational theories, open terms that break advanced symmetries while preserving physical ones are not automatically consistent; they are allowed only if they lead to deformed identities among the equations of motion. We explicitly construct such a term in open gravity and show that it leads to a consistent deformation of the diffeomorphism identities.

South Korea

Perseas Christodoulidis

Emergent structures and consistency of open EFTs

We investigate the dynamics of massive test particles around a static black hole in nonlocal gravity and examine the corresponding properties of high-frequency quasi-periodic oscillations (HF QPOs), constraining the nonlocal parameter to $$\alpha /M \le 0.452$$ . We show that the nonlocal parameter $$\alpha $$ enhances the effective potential $$V_{\text {eff}}$$ and leads to a systematic reduction in the energy $$\mathcal {E}$$ and angular momentum $$\mathcal {L}$$ of circular orbits. Consequently, the innermost stable circular orbit (ISCO) radius, along with the associated energy and angular momentum, decreases monotonically with $$\alpha $$ , while the radiative efficiency increases, reaching a maximum of approximately $$8.9\%$$ . We further analyze the fundamental orbital frequencies of test particles and find that, due to the spherical symmetry of the spacetime, the Keplerian frequency $$\Omega _{\phi }$$ and the vertical epicyclic frequency $$\Omega _{\theta }$$ coincide and are suppressed by $$\alpha $$ , whereas the radial epicyclic frequency $$\Omega _{r}$$ is enhanced. The impact of $$\alpha $$ on several twin-peak HF QPO models is examined, revealing that $$\alpha $$ increases both the lower and upper bounds of the predicted QPO frequency ranges. By imposing the $$2\nu _U = 3\nu _L$$ resonance condition, we analyze the resonant radius, upper QPO frequency, maximum allowed black hole mass, and the time delay between the shadow and QPO signals. We find that the resonant radius decreases with $$\alpha $$ , while the upper QPO frequency increases, spanning the range $$\nu _U \sim (673/M$$ – $$4360/M)\textrm{Hz}$$ . When the Tolman–Oppenheimer–Volkoff limit is imposed, the upper frequency is further constrained to $$\nu _U \lesssim 1450$$ Hz. Combining astronomical observations for the classification of QPOs, where $$\nu _U \ge 100$$ Hz, the black hole mass in the nonlocal gravity should satisfy $$M \lesssim 43.6M_\odot $$ . Although the radial separation between the resonant radius and the photon sphere decreases with $$\alpha $$ , the associated gravitational time delay increases, remaining below $$\sim 1.3\textrm{ms}$$ and thus negligible for current observational capabilities.

Tao-Tao Sui

Chen Long

Ye Zhang

The properties and predictions of quasi-periodic oscillations around a black hole in nonlocal gravity

We discuss how to model the surface of celestial bodies (such as stars) in quantum gravity to ensure the regularity of quantum corrections to classical solutions of general relativity at the surface of such bodies. Specifically, we use the Vilkovisky–DeWitt unique effective action to calculate universal quantum corrections to the exterior metric for a class of stellar models. Previous descriptions, obtained via a Heaviside density profile, are “pathological” at the surface of the star due to the divergence of the metric functions and associated curvature invariants. Introducing a modified version of the Tolman VII density profile, we determine the minimal degree of differentiability required for this function to generate regular quantum corrections at the star’s surface.

United Kingdom

Xavier Calmet

Marco Sebastianutti

On modelling the surfaces of celestial bodies in quantum gravity

We present the results of a multimethodological study aimed at investigating the interaction between graphene and tritium during its <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>β</mi></math>-decay to helium, under different levels of loading and geometrical configurations. We combine density-functional theory (DFT) to evaluate the interaction potentials, with calculations of the decay rate, in order to study the consequences that the presence of the substrate has on the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>β</mi></math>-decay spectrum of tritium. We determine the shape of the event rate, accounting for the effects of (part of) the corresponding condensed-matter degrees of freedom. In the context of future neutrino experiments, our results provide important information aimed at the optimization of hosting material. Furthermore, our work outlines a novel theoretical and computational scheme to account for the different timescales involved in the process and to address a question at the boundary between high- and low-energy physics. This requires nonconventional declinations of DFT combined with full quantum treatments of the nuclear configuration involved in the decay process. Our results pave the way for future studies aimed at determining the physics reach of upcoming neutrino mass experiments.

United States

Andrea Casale

Italy

Angelo Esposito

Guido Menichetti

Valentina Tozzini

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>β</mi></math>-decay spectrum of tritiated graphene: Combining nuclear quantum mechanics with density functional theory

What flavor structure of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi></math>-channel thermal dark matter remains compatible with current flavor physics and direct detection bounds? We broadly chart the space of hypotheses using the framework of flavor symmetries and their breaking patterns. We then focus on scenarios in which the fermionic dark matter and its scalar mediator are flavor singlets, falling into the class of rank-1 flavor violation. For two representative benchmarks, quarkphilic (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>q</mi><mi>L</mi></msub></math>) and leptophilic (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>e</mi><mi>R</mi></msub></math>), we perform a comprehensive phenomenological analysis, fitting the relic abundance and examining the interplay among flavor observables, direct detection, and collider searches. Our results quantify the allowed deviations from flavor-symmetric limits and assess the discovery prospects in future flavor and direct detection experiments.