We study classical background electric fields and the Schwinger effect in de Sitter space. We show that a constant electric field in de Sitter requires the photon to have a tachyonic mass proportional to the Hubble scale. This has physical implications for the induced Schwinger current that affect its IR behaviour. To study this, we recompute the Schwinger current in de Sitter space for charged fermions and minimally coupled scalars, imposing a physically consistent renormalization condition. We find a $\textit{finite and positive}$ Schwinger current even in the massless limit. This is in contrast to previous calculations in the literature, which found a negative IR divergence. We also obtain the first result for the Schwinger current of a non-minimally coupled scalar, including the conformally coupled case, which we find exhibits behaviour very similar to that of the fermion current. Our results may have physical implications for both magnetogenesis and inflationary dark matter production.

Spain

Mar Bastero-Gil

Portugal

Paulo B. Ferraz

António Torres Manso

Slovenia

Italy

Lorenzo Ubaldi

Roberto Vega-Morales

Schwinger current in de Sitter space * This work has been partially supported by Junta de Andalucía Projects P21-00199 and A-FQM-472-UGR20 (FEDER funds); SRA (10.13039/501100011033) and ERDF (PID2022-139466NB-C21) (R.V.M.); PID2022-140831NB-I00, funded by MICIU/AEI/10.13039/501100011033 and FEDER, UE (M.B.G., A.T.M.); by FCT CERN (10.54499/2024.00252.CERN) (M.B.G., A.T.M., P.F.); FCT Grant No. SFRH/BD/151475/2021 and 10.54499/SFRH/BD/151475/2021 (P.F.). LU is supported by the Slovenian Research Agency under research core funding No. P1-0035 and by research grants J1-60026 and J1-4389. This article is based upon work from COST Action COSMIC WISPers CA21106, supported by COST (European Cooperation in Science and Technology). R.V.M. thanks the Mainz Institute for Theoretical Physics (MITP) of the Cluster of Excellence PRISMA$^{+}$ (Project ID 390831469) for its hospitality and partial support during the completion of this work

Precise measurements of Higgs decays into quarks and gluons are essential for probing the Yukawa couplings of the Higgs boson and testing the flavor structure of the Standard Model. We investigate the process $\textit{e}$ $\textit{e}$ → $\textit{ZH}$ at $$ \sqrt{s} $$ = 240 GeV at a future $\textit{e}$ $\textit{e}$ Higgs factory, taking the CEPC design as a benchmark. The analysis focuses on events with $$ Z\to \nu \overline{\nu} $$ and hadronic Higgs decays $$ H\to b\overline{b} $$ , $$ c\overline{c} $$ , $$ s\overline{s} $$ and $\textit{gg}$. Jet flavor is identified using state-of-the-art particle-level deep neural network taggers (ParticleNet, Particle Transformer and More-Interaction Particle Transformer), whose per-jet outputs are combined with global event observables in a two-stage analysis employing XGBoost classifiers to separate the four Higgs decay modes from the dominant two- and four-fermion Standard Model backgrounds. Assuming an integrated luminosity of 20 ab , we obtain projected relative precision on $\textit{σ}$($\textit{ZH}$) × Br($\textit{H}$ → $\textit{X}$) of 0.17% for $\textit{X}$ = $$ b\overline{b} $$ , 1.06% for $$ c\overline{c} $$ , 0.50% for $\textit{gg}$ and 68% for $$ s\overline{s} $$ . Compared with the CEPC published results, the precisions for $$ H\to c\overline{c} $$ and $\textit{H}$ → $\textit{gg}$ are improved by about 43% and 29%, respectively. For $$ H\to s\overline{s} $$ we present a quantitative sensitivity estimation corresponding to a statistical significance of about 1.5$\textit{σ}$. These results highlight the potential of deep-learning-based jet flavor tagging for precision studies of Higgs decays at future $\textit{e}$ $\textit{e}$ Higgs factories.

China

Xinzhu Wang

Yifan Zhu

Chunxiang Zhu

Jianfeng Jiang

Manqi Ruan

Kun Wang

Haijun Yang

Yongfeng Zhu

Deep-learning jet flavor tagging for precision hadronic Higgs measurements at future $\textit{e}$ + $\textit{e}$ − Higgs factories

We combine spectral- and split representations to factorize multi-loop momentum space diagrams, in the Schwinger-Keldysh formulation for cosmological correlators, with massive scalars in the loop. This allows us to extend the resummation of loop contributions from flat to de Sitter space. Furthermore, in our split representation the signal part of the correlators can be identified directly on the integrand level from the spectral function. We apply this to describe the non-perturbative flow of the EFT background and the cosmological collider signals in a large-$\textit{N}$ model.

Germany

Jonathan Gräfe

Ivo Sachs

Split representations and bubble resummation for massive de Sitter correlators

Hard scattering events in high-energy collisions produce highly virtual partons that subsequently fragment into collimated hadronic cascades. When such partonic showers evolve in a QCD medium, as in deep-inelastic scattering or heavy-ion collisions, the resulting multi-particle distributions encode information about the surrounding matter. Decades of theoretical developments have led to a consistent and order-by-order improvable perturbative description of the shower. This description needs, however, the non-perturbative input that encodes the structure of the hadronic matter. The determination of such input remains challenging within conventional computational approaches, thereby limiting the applicability of the approach. In this work, we develop a framework that employs quantum simulation techniques to compute multi-particle processes in such environments by mapping partonic cross-sections to quantum circuits. As benchmarks, we analyze dipole formation and the QCD antenna radiation pattern at leading order in the strong coupling constant, comparing the results with analytic estimates in simplified limits. The quantum circuit formulation here introduced naturally extends to higher perturbative orders and enables amplitude-level computations in complex matter backgrounds. This provides a systematic foundation for applying quantum information science methods to study multi-particle dynamics in QCD media.

Switzerland

João Barata

Meijian Li

Wenyang Qian

Carlos Salgado

João Silva

Quantum simulating multi-particle processes in high energy nuclear physics: dijet production and color (de)coherence

We compute the complete two-loop unrenormalized electroweak corrections to the Higgsstrahlung process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>H</mi><mi>Z</mi></math> at future Higgs factories. Our result for a given center-of-mass energy is expressed as a piecewise function defined by several deeply expanded power series, which has high precision and can be further manipulated efficiently. We find that the finite part of the unrenormalized two-loop electroweak corrections can contribute a few thousandths, which might indicate their importance to match the precision of future Higgs factories. This work represents the first complete calculation of the unrenormalized two-loop electroweak corrections for processes with four external particles.

Xiang Chen

Xin Guan

Chuan-Qi He

Zhao Li

United Kingdom

Xiao Liu

Yan-Qing Ma

Complete two-loop unrenormalized electroweak corrections to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>H</mi><mi>Z</mi></math>

The next generation of electron–positron colliders will require unprecedented precision in both theory and experiment. Sophisticated software frameworks are essential to evaluate detector concepts, optimize designs, and simulating physical processes. In this context, Monte Carlo (MC) event generators play a central role, enabling realistic simulations of Standard Model processes and providing the basis for physics studies. However, technical consistency across different generators remains critical, particularly in domains where agreement is expected. To address this need, we present , a Python-based package that automates the benchmarking process for MC generators. The tool translates universal physics inputs into generator-specific configurations, ensuring consistency, reproducibility, and reduced human error. Its modular design allows for straightforward integration of additional generators, supports batch processing, and provides compatibility with the Key4hep software stack.

Poland

Alan Price

Dirk Zerwas

Configuration and benchmarking of $$\textrm{e}^+\textrm{e}^-$$ processes with k4GeneratorsConfig

We study neutrino nonstandard interactions (NSI) induced by the trilinear <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>L</mi><mi>i</mi></msub><msub><mi>L</mi><mi>j</mi></msub><msubsup><mi>E</mi><mi>k</mi><mi>c</mi></msubsup></math> (LLE) couplings in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>R</mi></math>-parity-violating supersymmetry in a split-family spectrum where third-generation sleptons can be comparatively light. We systematically classify the relevant coupling patterns, derive the corresponding effective interactions and NSI parameters, and confront the resulting parameter space with a broad set of experimental constraints. We find that percent-level NSI can be realized in selected channels, with the largest magnitudes reaching <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>e</mi><mi>e</mi></mrow></msub><mo>≃</mo><mn>8</mn><mo>%</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>μ</mi><mi>μ</mi></mrow></msub><mo>≃</mo><mn>3.8</mn><mo>%</mo></math>, while other entries are typically restricted to the subpercent level (including <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>μ</mi><mi>τ</mi></mrow></msub><mo>≃</mo><mo>−</mo><mn>0.3</mn><mo>%</mo></math> in the viable off-diagonal case). We also highlight the structural origin of the different constraint patterns between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>τ</mi><mo stretchy="false">˜</mo></mover><mi>R</mi></msub></math>- and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>τ</mi><mo stretchy="false">˜</mo></mover><mi>L</mi></msub></math>-mediated scenarios and comment on the relation to the Zee model.

United States

Fang Xu

Neutrino nonstandard interactions from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>L</mi><mi>L</mi><mi>E</mi></math>-type <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>R</mi></math>-parity violation

Atmospheric neutrinos provide a unique avenue to probe theories beyond the Standard Model (BSM) over a wide range of energies and path lengths. The theory of nonstandard interactions (NSI) of neutrinos is one of the important BSM scenarios, which can modify flavor oscillations of atmospheric neutrinos traveling through the Earth. In this work, we use a high-purity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>μ</mi></msub></math> charged-current (CC) sample of atmospheric neutrinos from IceCube DeepCore with a livetime of 7.5 years to search for the NSI parameters <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>e</mi><mi>μ</mi></mrow></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>e</mi><mi>τ</mi></mrow></msub></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>e</mi><mi>e</mi></mrow></msub><mo>−</mo><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>μ</mi><mi>μ</mi></mrow></msub></mrow></math>. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>μ</mi></msub></math> CC events mainly come from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>μ</mi></msub></math> survival channel having no significant dependence on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>δ</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math>. Therefore, the constraints on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>e</mi><mi>μ</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>e</mi><mi>τ</mi></mrow></msub></math> obtained using this <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>μ</mi></msub></math> CC sample are expected to be free from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>δ</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math>-degeneracy. The data sample is found to be in agreement with the standard neutrino interactions. Therefore, we place bounds on these NSI parameters that are consistent with and comparable to existing experimental constraints. These <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>δ</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math>-free constraints from IceCube DeepCore are complementary to those from the long-baseline neutrino oscillation experiments, where the appearance channel depends on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>δ</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math>.

India

J Krishnamoorthi

Anil Kumar

Sanjib Kumar Agarwalla

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>δ</mi></mrow><mrow><mi>C</mi><mi>P</mi></mrow></msub></mrow></math>-free constraints on NSI parameters <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>e</mi><mi>μ</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϵ</mi><mrow><mi>e</mi><mi>τ</mi></mrow></msub></math> using high-purity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ν</mi><mi>μ</mi></msub></math> CC events at IceCube DeepCore

This article presents a detailed study of an Ayón–Beato–García–de Sitter black hole surrounded by a quintessential field and cloud of strings. We begin by observing the metric and examining how different parameter choices impact the spacetime structure. Specifically, we study scenarios with positive (1/2) $$\Lambda $$ and changing other parameters. We then study particle geodesic motion, examining the effect of the modified spacetime on neighboring massive and massless particles, where we also discuss the stability for timelike geodesics. We then calculate the expression for the energy corresponding to circular orbits, examine the Lyapunov exponent and geodesic precession frequency for various values, and demonstrate how different parameters impact the evolution. Lastly, we utilize the null geodesics of photons to investigate the gravitational lensing properties of a black hole enveloped by quintessence and a cloud of strings by employing finite-distance formalism. The overall effort will allow us to understand the dynamical and stability properties of spacetime with small perturbations. In conclusion, a comprehensive study of the impacts of de-Sitter black holes on particle dynamics and motion in curved geometry has been provided in this article by considering additional fields.

Saudi Arabia

I. Shakir

Pakistan

Z. Yousaf

A. Farhat

Türkiye

I. Siddique

Azerbaijan

M. Bhatti

Geodesic dynamics of an Ayón–Beato–García–de Sitter black hole in the presence of quintessence and a cloud of strings

A sensitivity study of $ \bar{K}_1(1270) $ decay-mode measurements is performed using semileptonic $\textit{D}$-meson decays. The BESIII experiment is used as a case study, in which a simultaneous analysis of $ \bar{K}_1(1270) $ decays to the four three-body final states $ K^-\pi^+\pi^- $ , $ K^-\pi^+\pi^0 $ , $ K_S^0\pi^+\pi^- $ , and $ K_S^0\pi^-\pi^0 $ is presented, and a model-independent determination of $ {\cal{B}}(\bar{K}_1(1270)\to \bar K\pi\pi) $ that does not require detailed knowledge of intermediate resonant contributions is proposed.

Ying'ao Tang

Liang Sun

Panting Ge

Menghao Wang

Sensitivity study of ${\bar{K}_1(1270)}$ decay dynamics using four ${D\to \bar{K}_1(1270)(\to \bar K\pi\pi)e^+\nu_e}$ decay channels * Supported by the National Natural Science Foundation of China (NSFC) (12575102, 12192265, 12405094) and Science and Technology R&D Program Joint Fund Project of Henan Province (225200810030)