<p>Radio pulses generated by cosmic-ray air showers can be used to reconstruct key properties like the energy and depth of the electromagnetic component of cosmic-ray air showers. Radio detection threshold, influenced by natural and anthropogenic radio background, can be reduced through various techniques. In this work, we demonstrate that convolutional neural networks (CNNs) are an effective way to lower the threshold. We developed two CNNs: a classifier to distinguish radio signal waveforms from background noise and a denoiser to clean contaminated radio signals. Following the training and testing phases, we applied the networks to air-shower data triggered by scintillation detectors of the prototype station for the enhancement of IceTop, IceCube’s surface array at the South Pole. Over a four-month period, we identified 554 cosmic-ray events in coincidence with IceTop, approximately five times more compared to a reference method based on a cut on the signal-to-noise ratio. Comparisons with IceTop measurements of the same air showers confirmed that the CNNs reliably identified cosmic-ray radio pulses and outperformed the reference method. Additionally, we find that CNNs reduce the false-positive rate of air-shower candidates and effectively denoise radio waveforms, thereby improving the accuracy of the power and arrival time reconstruction of radio pulses.</p>

United States

R. Abbasi

Germany

M. Ackermann

New Zealand

J. Adams

S.K. Agarwalla

Belgium

J.A. Aguilar

Denmark

M. Ahlers

J.M. Alameddine

S. Ali

N.M. Amin

K. Andeen

C. Argüelles

Y. Ashida

S. Athanasiadou

S.N. Axani

R. Babu

X. Bai

J. Baines-Holmes

A. Balagopal V.

S.W. Barwick

S. Bash

V. Basu

R. Bay

J.J. Beatty

J. Becker Tjus

P. Behrens

Sweden

J. Beise

C. Bellenghi

B. Benkel

S. BenZvi

D. Berley

Italy

E. Bernardini

D.Z. Besson

E. Blaufuss

L. Bloom

S. Blot

I. Bodo

F. Bontempo

J.Y. Book Motzkin

C. Boscolo Meneguolo

S. Böser

O. Botner

J. Böttcher

J. Braun

B. Brinson

Canada

Z. Brisson-Tsavoussis

Australia

R.T. Burley

D. Butterfield

M.A. Campana

K. Carloni

J. Carpio

S. Chattopadhyay

N. Chau

Z. Chen

D. Chirkin

S. Choi

B.A. Clark

A. Coleman

P. Coleman

G.H. Collin

D.A. Coloma Borja

A. Connolly

J.M. Conrad

R. Corley

D.F. Cowen

C. De Clercq

J.J. DeLaunay

D. Delgado

T. Delmeulle

S. Deng

P. Desiati

K.D. de Vries

G. de Wasseige

T. DeYoung

J.C. Díaz-Vélez

S. DiKerby

M. Dittmer

A. Domi

L. Draper

L. Dueser

D. Durnford

K. Dutta

M.A. DuVernois

T. Ehrhardt

L. Eidenschink

A. Eimer

P. Eller

E. Ellinger

D. Elsässer

R. Engel

H. Erpenbeck

W. Esmail

S. Eulig

J. Evans

P.A. Evenson

K.L. Fan

K. Fang

Japan

K. Farrag

A.R. Fazely

Taiwan

A. Fedynitch

N. Feigl

Identification and denoising of radio signals from cosmic-ray air showers using convolutional neural networks

We present a complete analytic and semi-analytic study of gravitational collapse and primordial black hole (PBH) formation in the quadratic $\textit{f}$($\textit{R}$) model $$f(R)=R+\alpha R^2$$ . We first derive the perturbative expansion around General Relativity (GR), working to first order in the small parameter $$\alpha $$ . For a collapsing flat FLRW dust interior we compute the explicit first-order corrections to the scale factor, the stellar radius, and the horizon formation time. We then use these results to infer the expected trend in the PBH formation threshold $$\delta _c$$ , rather than a direct quantitative determination. Within this perturbative framework, the quadratic correction modifies the dust collapse dynamics at first order, while the flat radiation-dominated background does not receive a nontrivial correction at the same order. As result, any modification of PBH formation in the radiation era must arise from nonlinear or non-perturbative effects. The perturbative analysis therefore provides qualitative insight into how curvature corrections influence collapse, particularly in high-curvature regimes. To access this regime we reformulate the theory in the Einstein frame, where the model becomes GR plus the scalaron field $$\phi $$ with the Starobinsky potential. We provide the complete ODE system governing both the cosmological background and the evolution of an overdense closed FLRW patch. This system can be numerically integrated to obtain the critical overdensity $$\delta _c(k)$$ for PBH formation near the end of inflation.

Egypt

G. Nashed

Saudi Arabia

A. Eid

Primordial black hole formation in $$f(R)=R+\alpha R^2$$ gravity: perturbative and non-perturbative analysis

We constrain the Hu–Sawicki and Starobinsky $\textit{f}$($\textit{R}$) gravity models utilizing current electromagnetic (PantheonPlus + cosmic chronometers [PP+CC], Planck, and DESI2) datasets and simulate standard siren (SS) catalogs based on the resulting best-fit parameters. We demonstrate that the simulated SS data provide complementary sensitivity to the modified gravitational wave propagation friction term, thereby enhancing the discriminating power between $\textit{f}$($\textit{R}$) gravity and the $$\varLambda $$ CDM model. However, we note that standard sirens do not offer a viable resolution to the Hubble tension in this analysis, as the inferred constraints are predominantly driven by the fiducial cosmologies adopted in the simulations. Regarding the specific models, we find that for the Hu–Sawicki scenario, several data combinations favor $$F_{RR0}<0$$ , implying potential theoretical instabilities. And, for the Starobinsky model, while electromagnetic-only constraints are nearly symmetric between the two parameter branches ( $$b<0$$ and $$b>0$$ ), the inclusion of SS constraints introduces mild asymmetries, revealing the sensitivity of SS observables to the curvature dependence of the theory. Future truly independent standard siren observations would be crucial for a definitive assessment of $\textit{f}$($\textit{R}$) gravity as an alternative to $$\varLambda $$ CDM.

China

Yi Zhang

Xuanjun Niu

Xianfu Su

Dong-Ze He

The standard siren tests of viable $\textit{f}$($\textit{R}$) cosmologies

The present study analyzes anisotropic compact objects coupled with the electromagnetic field within the context of <italic>f</italic>( <italic>R, T</italic>) gravity. We obtain two novel solutions of modified field equations for a static charged spacetime. To simplify the system, we employ two different assumptions for the radial metric component and specific anisotropic pressure profiles, and obtain exact analytical solutions. The governing field equations in both models yield differential equations whose general solutions contain undetermined constants. These constants are evaluated through the junction conditions between the interior and the exterior Reissner-Nordstr&#246;m spacetimes across the boundary surface. In this regard, we also impose the condition that the radial pressure drops to zero on the star&#8217;s interface. Furthermore, we examine the fundamental prerequisites that must be fulfilled for physical existence of compact objects. For graphical analysis, we consider the observed data of two stars, LMC X-4 and SMC X-4, together with multiple parametric values. Our findings demonstrate that both resulting solutions satisfy the essential physical requirements under the considered modified gravitational framework for certain values of the charge and model parameter.

Pakistan

Hira Shadab

Azerbaijan

M. Sharif

Tayyab Naseer

Role of electric charge in the construction of relativistic stellar solutions in <italic>f</italic>( <italic>R, T</italic>) gravity

The <italic>f</italic>( <italic>R, T</italic>) theory of gravity extends general relativity (GR) by allowing the gravitational Lagrangian to depend on both the Ricci scalar <italic>R</italic> and the trace of the energy-momentum tensor <italic>T</italic>. The resulting matter-geometry coupling introduces additional dynamical effects that may account for the late-time acceleration of the universe without invoking dark energy. In the present work, we focus instead on the early-time regime and investigate the corresponding quantum cosmological dynamics. We analyze a Friedmann&#8211;Lemaitre&#8211;Robertson&#8211;Walker (FLRW) universe within the <italic>f</italic>( <italic>R, T</italic>) framework, employing Schutz&#8217;s perfect fluid formalism to extract a time parameter emerging from the matter sector itself. This approach is particularly well motivated in <italic>f</italic>( <italic>R, T</italic>) gravity where the coupling between geometry and the trace of the energy-momentum tensor makes the matter sector an explicit part of the minisuperspace dynamics. The gravitational Hamiltonian, canonical momenta, and potential are derived, leading to the corresponding Schr&#246;dinger&#8211;Wheeler&#8211;DeWitt (SWDW) equation. The wave function of the universe is obtained for specific forms of <italic>f</italic>( <italic>R, T</italic>), and the results are compared with previous studies in <italic>f</italic>( <italic>R</italic>) and <italic>f</italic>( <italic>R, T</italic>) models, highlighting the role of matter-geometry coupling in the emergence of quantum cosmological dynamics.

Türkiye

Serkan Doruk Hazinedar

Yaghoub Heydarzade

Shahram Jalalzadeh

Quantum cosmology in <italic>f</italic>( <italic>R, T</italic>) theory with Schutz&#8217;s perfect fluid

We extract the non-perturbative heavy quark effective theory (HQET) parameters from the inclusive semi-leptonic decay $ \Lambda_c^+ \to X e^+ \nu_e $ . Unlike charmed mesons produced near the threshold, $ \Lambda_c^+ $ baryons produced in $ e^+e^- $ annihilation exhibit a complex momentum distribution, which makes the transformation of the electron energy spectrum from the laboratory frame to the $ \Lambda_c^+ $ rest-frame non-trivial. To address this issue, we develop a novel Bayesian inference method to reconstruct the electron energy moments in the $ \Lambda_c^+ $ rest-frame. We determine the HQET parameters $ \mu_\pi^2(\Lambda_c^+) $ and $ \rho_D^3(\Lambda_c^+) $ for the first time using a purely data-driven approach by performing a global fit of theoretical predictions in the 1S mass scheme to these extracted moments.

Dong Xiao

Kangkang Shao

Bayesian extraction of HQET parameters from the inclusive semi-leptonic decay of the $ {\Lambda_c^+} $ baryon * Supported in part by Natural Key R&D Program of China (2023YFA1609400) and National Natural Science Foundation of China (NSFC) (12105127)

The strong coupling $\textit{α}$ is determined with high precision from fits to lattice QCD simulations on the static energy. Our theoretical setup relies on R-improving the three-loop fixed-order prediction for the static energy by removing its $\textit{u}$ = 1/2 renormalon and summing up the associated large (infrared) logarithms which, in combination with radius-dependent renormalization scales (called profile functions) extends the validity of perturbation theory to distances up to ~ 0.5 fm. Furthermore, we resum large ultrasoft logarithms to N LL accuracy using renormalization group evolution. We have checked that the standard four-loop R-evolution treats N LL and higher remnants in a non-symmetric way, hence we also account for this potential bias. Our estimate of the perturbative uncertainty is based on a random scan over the parameters specifying the profile functions and the treatment of R-evolution. We also devise a method to statistically combine into a single dataset results from independent simulations which use different lattice spacing and cover various ranges, which can be used to carry out fits in a much faster way. We explore the dependence of the extracted $\textit{α}$ value on the smallest and largest distances included in the dataset, on how R-evolution is treated, on how the fit is performed, and on the accuracy of ultrasoft resummation. From our final analysis, after evolving to the $\textit{Z}$-pole we obtain $$ {\alpha}_s^{\left({n}_f=5\right)}\left({m}_Z\right)=0.1170\pm 0.0009 $$ , compatible with the world average with the same incertitude.

Spain

Jose Mena-Valle

Vicent Mateu

Pablo Ortega

A precise $\textit{α}$ $\textit{s}$ determination from the R-improved QCD static energy

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)

We study the generalized cusp anomalous dimension, or quark-antiquark potential on the three-sphere, in the presence of a large $\textit{R}$-charge $\textit{L}$ and at strong coupling. Considering the insertion of a local scalar operator of charge $\textit{L}$ on a cusped Wilson loop, we investigate the general solution of the dual string configuration for any value of cusp angles, paying particular attention to the different ranges of the physical parameters and obtaining a unified description that simultaneously captures the near BPS, the antiparallel lines and the large-$\textit{L}$ regimes. We observe, in the limit of small separation between the lines, a non-analytic change in the behavior of the cusp anomaly at a critical value of $\textit{L}$: one crosses from a region dominated by the familiar Coulomb-like singularity to a “deconfined” situation describing the leading Lüscher corrections at large $\textit{L}$ of the generalized cusp anomalous dimension. We derive the equations for small fluctuations around the classical string solution, generalizing previous analysis of the uncharged case, and we study the behavior of the spectrum near the transition region. Finally, we speculate on the field theory origin of the transition and on its implications for the fusion of Wilson lines.

Davide Bonomi

Valentina Forini

Iceland

Valentina Puletti

Luca Griguolo

Domenico Seminara

Probing the dynamics of stringy flux tubes with large $\textit{R}$-charge

The $\textit{μ}$-$\textit{e}$ conversion process is one of the most powerful ways to test lepton-flavor-violating (LFV) interactions involving charged leptons. The standard model with massive neutrinos predicts an extremely low rate for $\textit{μ}$-$\textit{e}$ conversion, making this process an excellent probe for testing LFV arising from new physics. Among many theoretical models that can induce LFV, the Supersymmetric model with R-parity violating interactions is one of the most studied for $\textit{μ}$-$\textit{e}$ conversion. In this work, we revisit trilinear $\textit{R}$-parity violating interactions for $\textit{μ}$-$\textit{e}$ conversion, considering renormalization group (RG) running effects from high to low energy scales. The $\textit{μ}$-$\textit{e}$ conversion, $\textit{μ}$ → $\textit{eγ}$, and $\textit{μ}$ → $\textit{eee}$ experimental data are compared to give upper limits on the relevant 15 combinations of the trilinear $\textit{λ′}$ couplings and 6 combinations of the $\textit{λ}$ couplings, certain of which are underexplored in previous studies. We find that RG running effects influence the limits by no more than 30% in most cases, but can improve constraints by ~80% in certain combinations, which cannot be neglected. In the near future, COMET and Mu2e are expected to begin data-taking and aim to provide the most stringent constraints on $\textit{μ}$-$\textit{e}$ conversion. These next-generation $\textit{μ}$-$\textit{e}$ experiments have the ability to give much more comprehensive examinations on most trilinear coupling combinations than the $\textit{μ}$ → $\textit{eγ}$ and $\textit{μ}$ → 3$\textit{e}$ decay experiments. The $\textit{μ}$-$\textit{e}$ experiments will not only deepen our understanding of LFV but also provide a crucial way to examine the underlying new physics contributions.

Yu-Qi Xiao

Xiao-Gang He

Hong-Yi Niu

Rong-Rong Zhang

Revisiting $\textit{μ}$-$\textit{e}$ conversion in $\textit{R}$-parity violating SUSY