Using the pinch technique, we determine the one-loop vertices of weak interactions in the B-LSSM and incorporate their pinch contributions into the gauge boson self-energies. Compared to the definitions of the $\textit{S}$, $\textit{T}$, and $\textit{U}$ parameters in the Standard Model based on the $S U(2)_L \otimes U(1)_Y$ group, the corresponding parameters in the local B-L gauge symmetry (B-LSSM) are modified. We present these redefined $\textit{S}$, $\textit{T}$, and $\textit{U}$ parameters and demonstrate the convergence of the results. In the framework of the low-energy effective Lagrangian for weak interactions, the $\textit{S}$, $\textit{T}$, and $\textit{U}$ parameters can be expressed as functions of specific parameters in the B-LSSM. The updated experimental and fitting results strongly constrain the parameter space of the B-LSSM.

China

Sheng-Kai Cui

Ke-Sheng Sun

Yu-Li Yan

Jin-Lei Yang

Tai-Fu Feng

$\textit{S}$, $\textit{T}$, $\textit{U}$ parameters in the B-LSSM * Supported by the Natural Science Foundation of Guangxi Autonomous Region (2022GXNSFDA035068), the Natural Science Foundation of Hebei Province (A2022104001), and the Foundation of Baoding University (2023Z01)

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)

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 compute the contour integral for the partition function of an $$ \mathcal{N} $$ = 2 SU(2) topologically twisted theory on $$ {\mathbbm{CP}}^2 $$ , dimensionally reducing from an $$ \mathcal{N} $$ = 1 theory on $\textit{S}$ . Earlier works presented the partition function as a sum over three equivariant fluxes, one for each toric divisor of $$ {\mathbbm{CP}}^2 $$ . Our result depends only on a single physical flux, assigned to the non-trivial two-cycle of the manifold. The reduced summation over fluxes is compensated by a contour of integration, arising from a different solution of the BPS equations, which captures more poles in each topological sector. As our observable involves a position-dependent Yang-Mills coupling, we compute new equivariant invariants of $$ {\mathbbm{CP}}^2 $$ , which reduce to Donaldson invariants in the non-equivariant limit. Stability conditions of gauge bundles over $$ {\mathbbm{CP}}^2 $$ appear intrinsically via the dimensional reduction.

Italy

Lorenzo Ruggeri

Contour integral for the partition function of $$ \mathcal{N} $$ = 2 topologically twisted on $$ {\mathbbm{CP}}^2 $$ and physical fluxes

We analyze Morris Thorne-type traversable wormhole solutions in endowed with a topological global monopole charge and a cosmological constant, by adopting an anisotropic fluid source in the context of <italic>D</italic>-dimensional Einstein gravity. To continue our systematic investigation, we consider two trigonometric-hyperbolic shape functions. The geometric analysis (2D/3D embeddings and flare-out conditions) confirms regular, traversable throat geometries. From the field equations, we derive explicit expressions for the energy density and directional pressures and show that the radial null energy condition is generically violated at the throat, signaling the presence of exotic matter, while this condition tangentially can remain nonnegative for suitable parameter choices. The active gravitational mass shows negative values near the throat, indicating a localized exotic matter contribution; however, the anisotropy parameter is positive in representative configurations, producing outward directed stresses that assist throat stability. The stability is further supported by an adiabatic index approach that exceeds the relativistic threshold in the explored parameter regimes, and to measure the total exotic matter budget, we utilize the volume integral quantifier approach within considered gravity scenario. This work offers valuable theoretical insights into wormhole solutions in higher-dimensional Einstein gravity, contributing to the broader understanding of hypothetical traversable wormholes in modified gravitational theories.

Azerbaijan

Pakistan

M. Yousaf

Saudi Arabia

Saad Aljaber

M. Zeeshan Gul

Jordan

Faisal Javed

A. Eid

Uzbekistan

Farkhod Botirov

Farruh Atamurotov

Physical features of global monopole charged traversable wormholes

We propose a novel method for extracting non-singlet (NS) fragmentation functions (FFs) of light charged hadrons from charge asymmetries measured in hadron fragmentation using data from both single-inclusive electron-positron annihilation and semi-inclusive deep-inelastic scattering processes. We determine the NS FFs for pions and kaons at next-to-next-to-leading order in Quantum Chromodynamics through a comprehensive uncertainty analysis. The extracted FFs reveal a scaling index of approximately 0.7 at large momentum fractions and low energy scales, a strangeness suppression factor of approximately 0.5, and universality in fragmentation of light mesons. Our findings establish a valuable benchmark for testing non-perturbative QCD models and Monte Carlo event generators, and serve as crucial inputs for future electron-ion colliders.

Jun Gao

Chong-Yang Liu

Bin Zhou

Determination of fragmentation functions from charge asymmetries in hadron production * The work of Jun Gao is supported by the National Natural Science Foundation of China (NSFC) (12275173), the Shanghai Municipal Education Commission (2024AIZD007) and open fund of Key Laboratory of Atomic and Subatomic Structure and Quantum Control (Ministry of Education)

The Schwinger effect, a non-perturbative mechanism for particle production in strong fields, plays a crucial role in understanding quantum vacuum decay and high-energy phenomena, including heavy-ion collisions (HIC). Although holographic quantum chromodynamics (QCD) models have been widely used to study this effect, most treatments assume isotropy or consider only a single type of anisotropy, neglecting the interplay between spatial and magnetic anisotropies that arise in realistic HIC scenarios. A unified framework accounting for both anisotropies is needed to accurately model particle production. We investigate the Schwinger effect in a twice anisotropic holographic QCD model incorporating both spatial and magnetic anisotropies. Using the anti-de Sitter/conformal field theory correspondence, we compute the total potential of a particle-antiparticle pair to quantify how these anisotropies influence pair production. Our results show that the magnetic field (parameterized by $c_B$ and $q_3$ ) enhances the Schwinger effect by lowering and narrowing the potential barrier, while increasing spatial anisotropy (controlled by $\nu$ ) suppresses the process by raising and widening the barrier. These findings demonstrate that magnetic and spatial anisotropies exert competing effects on particle production, emphasizing the necessity of treating both concurrently in holographic models. This work advances the theoretical description of the Schwinger effect in anisotropic environments, with implications for understanding non-equilibrium dynamics in HIC and other strongly coupled systems.

Wen-Bin Chang

Defu Hou

Schwinger effect in a twice anisotropic holographic model * Defu Hou's research is supported in part by the National Key Research and Development Program of China (2022YFA1604900). Additionally, Defu Hou receives partial support from the National Natural Science Foundation of China (NSFC) (12435009, 12275104). Wen-Bin Chang is supported by the Ph.D. Research Startup Project at Hubei Minzu University (RZ2500000857)

<p>We compute the complex, long-distance two-photon-exchange amplitude which contributes to the rare <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi mathvariant="normal">L</mi></msub><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> decay from lattice QCD. We use a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>24</mn><mn>3</mn></msup><mo>×</mo><mn>64</mn></math> physical-pion-mass gauge field ensemble at an inverse lattice spacing of 1.023 GeV and a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>QED</mi></mrow><mrow><mi>∞</mi></mrow></msub></mrow></math>-based formalism. Our implementation strategies for all five non-SU(3)-flavor-suppressed diagram topologies are given in detail. We achieve a 25% statistical precision on the dispersive part of this long-distance amplitude. This calculation is carried out with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2</mn><mo>+</mo><mn>1</mn></mrow></math> quark flavors and therefore requires the addition of counterterms to compensate for the absence of the Glashow-Iliopoulos-Maiani mechanism. These counterterms are not included in the current calculation and will be the subject of a second paper. Although a direct comparison to experiment cannot yet be made because of those omitted counterterms, the present exploratory calculation allows one to identify principal sources of statistical uncertainty in this calculation. The precision of our results is limited by the reconstruction of the physical contribution of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math> intermediate state, for which various strategies are tested and compared.</p>

United States

United Kingdom

Peter Boyle

En-Hung Chao

Norman Christ

Ceran Hu

Luchang Jin

Yidi Zhao

Exploratory calculation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi mathvariant="normal">L</mi></msub><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> decay from lattice QCD at physical pion mass

<p>A crucial step in extracting physical predictions from lattice quantum chromodynamics (QCD) simulations is the scale setting, i.e., the determination of the lattice spacing (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>a</mi></math>) in physical units. Herein, the relative scale setting for different <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>β</mi></math>’s is discussed, using the Landau gauge gluon propagator computed with large statistical ensembles. After setting the relative scales, finite size effects are observed in the ultraviolet regime and handled in an effective description, inspired in perturbation theory. The new devised procedure is efficient in handling the finite size effects, linking the lattice simulations with continuum perturbation theory for the high momenta regime. Furthermore, the procedure can be extended to handle other Green’s functions computed within lattice QCD simulations.</p>

Portugal

Orlando Oliveira

Paulo J. Silva

Using the Landau gauge gluon propagator to set the lattice physical scales and understanding the finite size effects

We compute the phase of the Euclidean gravity partition function on manifolds of the form $\textit{S}$ × $\textit{M}$ . We find that the total phase is equal to the phase in pure gravity on $\textit{S}$ times an extra phase that arises from negative mass squared fields that we obtain when we perform a Kaluza-Klein reduction to $\textit{S}$ . The latter can be matched to the phase expected for physical negative modes seen by a static path observer in $\textit{dS}$ . In the case of $\textit{S}$ × $\textit{S}$ the answer can be interpreted in terms of a computation in the static patch of $\textit{dS}$ or $\textit{dS}$ . We also provide the phase when we have a product of many spheres. We clarify the procedure for determining the precise phase factor. We discuss some aspects of the interpretation of this phase.

Victor Ivo

Juan Maldacena

Zimo Sun

Physical instabilities and the phase of the Euclidean path integral