High-precision regression of physical parameters from black hole images generated by General Relativistic Ray Tracing (GRRT) is essential for investigating spacetime curvature and advancing black hole astrophysics. However, owing to limitations in observational resolution, high observational costs, and imbalanced distributions of positive and negative samples, black hole images often suffer from data scarcity, sparse parameter spaces, and complex structural characteristics. These factors pose significant challenges to conventional regression methods based on simplified physical models. To overcome these challenges, this study introduces the Multiscale Adaptive Network (MANet), a novel regression framework grounded in deep learning. MANet integrates an Adaptive Channel Attention (ACA) module to selectively enhance features in physically informative regions. Meanwhile, a Multiscale Enhancement Feature Pyramid (MEFP) is employed to capture fine-grained spatial structures, such as photon rings and accretion disks, while alleviating information loss due to downsampling. Experimental evaluations on GRRT-simulated datasets demonstrate that MANet substantially improves parameter estimation accuracy and generalization capability in high-dimensional parameter spaces, outperforming existing baseline approaches. This framework presents a promising avenue for high-precision parameter regression in Event Horizon Telescope (EHT) data analysis and broader astrophysical imaging applications characterized by sparse and noisy data.

China

Jialei Wei

Ao Liu

Dejiang Li

Cuihong Wen

Physical parameter regression from black hole images using a multiscale adaptive neural network * Supported by the Natural Science Foundation of Hunan Province under grant No. 2023JJ30384; the National Natural Science Foundation of China under Grants No. 12374408; the University Students' Innovation and Entrepreneurship Training Program Project

The directed flow ( $$v_1$$ ) of charged hadrons ( $$h^{\pm }$$ ) in symmetric collision systems (O + O, Cu + Cu, Zr + Zr, Ru + Ru, Au + Au, and U + U) at $$\sqrt{s_{\textrm{NN}}} =$$ 200 GeV using string-melting version of A Multiphase Transport (AMPT-SM) model is reported. The $$v_1$$ as a function of pseudo-rapidity ( $$\eta $$ ) is obtained for transverse momentum ( $$p_{\textrm{T}}$$ ) ranges of 0.2 $$-$$ 2.0 GeV/$\textit{c}$ and 2.0 $$-$$ 5.0 GeV/$\textit{c}$. The dependence of $$v_1$$ -slope ( $$dv_1/d\eta $$ ) at mid-rapidity on $$p_{\textrm{T}}$$ range, collision centrality, and system size are discussed particularly in the context of the hard-soft asymmetry in the flow profiles of produced particles. In the AMPT-SM model, a system size independence of the magnitude of $$dv_1/d\eta $$ between Cu + Cu and Au + Au collisions at low- $$p_\textrm{T}$$ is observed, and this finding is similar to the observation from the STAR experiment at $$\sqrt{s_{\textrm{NN}}} =$$ 200 GeV. In contrast, a strong centrality and system size dependence, with the opposite sign of $$dv_1/d\eta $$ , is found for the high- $$p_{\textrm{T}}$$ charged hadrons. The AMPT-SM model demonstrates a clear violation of the expected scaling of charged hadrons $$(dv_1/d\eta )/A^{1/3}$$ across different colliding systems.

India

Kishora Nayak

Chile

Vipul Bairathi

System size dependence of charged hadrons directed flow at $$\sqrt{s_{NN}}$$ = 200 GeV using a multi-phase transport model

Within the framework of the next-to-minimal supersymmetric (SUSY) extension of the Standard Model (SM) with a local B-L gauge symmetry (N-B-LSSM), we study lepton flavor violating (LFV) $ \tau\rightarrow e M^+ M^- $ decays: $ \tau \rightarrow e \pi^+\pi^- $ , $ \tau \rightarrow e \pi^+K^- $ , and $ \tau \rightarrow e K^+K^- $ . Based on the latest experimental data, the influence of different sensitive parameters on the branching ratios is considered. It can be seen from the numerical analysis that the main sensitive parameters and LFV sources are non-diagonal elements corresponding to the initial and final leptons. This work can provide a basis for discovering the existence of new physics (NP).

Rong-Zhi Sun

Shu-Min Zhao

Shuang Di

Portugal

Xing-Xing Dong

Study of ${\boldsymbol\tau\rightarrow {\boldsymbol e M^+ M^-}}$ decays in N-B-LSSM * Supported by National Natural Science Foundation of China (NNSFC) (12075074), Natural Science Foundation of Hebei Province (A2023201040, A2022201022, A2022201017, A2023201041), Natural Science Foundation of Hebei Education Department (QN2022173), Post-graduate's Innovation Fund Project of Hebei University (HBU2024SS042), the Project of the China Scholarship Council (CSC) (202408130113). X. Dong acknowledges support from Fundação para a Ciência e a Tecnologia (FCT, Portugal) through the projects CFTP FCT Unit (UIDB/00777/2020, UIDP/00777/2020)

We use a modified relativistic quark model to study the properties of excited charmed and charmed strange mesons. We calculate the masses and wave functions of conventional charmed and charmed strange mesons incorporating both spin and $\textit{S}$-$\textit{D}$ mixing effects and fit parameters of the potential model with known experimental states using differential evolution techniques. Using leading Born-Oppenheimer expansion, we compute the spectrum and wave functions of the first gluonic excited state of charmed and charmed strange mesons. We examine the effects of gluonic excitation on the spectrum of the resulting hybrid mesons. Using our calculated spectrum and wave functions, we determine the radiative transitions of the conventional and hybrid open charm mesons. We compare our calculations with experimental data and other works. We expect our results will be beneficial in the detection of charmed and charmed strange conventional and hybrid mesons.

Pakistan

Saba Noor

Faisal Akram

Bilal Masud

Study of excited $\textit{D}$ and D$_{s}$ mesons in a relativized quark model * F. A. acknowledges HEC grant 20-15728/NRPU/R&D/HEC/2021, Pakistan

Lattice Monte Carlo simulations and the functional renormalization group (RG) are powerful approaches that allow for quantitative studies of nonperturbative phenomena such as bound-state formation, spontaneous symmetry breaking, and phase transitions. While results from both methods have recently shown remarkable agreement for many observables, e.g., in quantum chromodynamics, an analysis of deviations in certain quantities turns out to be challenging. This is because calculations with the two methods are based on different approximations, regularizations, and scale fixing procedures. In the present work, we present a framework for a more direct comparison by formulating the functional RG approach on a finite spacetime lattice. This removes all ambiguities of regularization, finite-size, and scale fixing procedures in concrete studies. By investigating the emergence of spontaneous symmetry breaking and phase transitions in a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi><mo stretchy="false">(</mo><mn>2</mn><mo stretchy="false">)</mo></math> scalar theory in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi><mo>=</mo><mn>1</mn></math>, 2, and 3 spacetime dimensions, we demonstrate at the example of the local potential approximation how this framework can be used to evaluate and compare the systematic errors of both approaches.

Germany

Niklas Zorbach

Jan Philipp Klinger

Owe Philipsen

Jens Braun

Lattice Monte Carlo meets the lattice functional renormalization group: A quantitative comparison

In this paper, we employ a bottom-up holographic QCD model to investigate the dissociation of charmonium states moving in a rotating medium by calculating their quasinormal modes. We begin by reviewing the holographic quarkonium spectrum at zero temperature. Then, we derive the equations of motion for heavy vector mesons propagating in a rotating plasma, separating the analysis into longitudinal and transverse directions relative to the wave vector. Additionally, we compute the charge diffusion constant in the rotating background and analyze the pole-skipping phenomenon, which emerges in the retarded Green’s function. Finally, we investigate the impact of rotation on the spin alignment of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> state in the helicity frame, utilizing the spectral function obtained from the holographic framework.

Luiz F. Ferreira

Dispersion relations and pole-skipping in a holographic charmonium model with rotating plasma

We address the phenomenological impact of a well-motivated class of scotogenic models regarding flavour and electroweak precision observables. In particular, and for the case of a “T1-2-A” variant, we carry out a full computation of the next-to-leading order corrections to leptonic Higgs and $\textit{Z}$-boson decays. In view of the evolution in the tension between theory and observation regarding the anomalous magnetic moment of the muon, we revisit previously drawn conclusions on operator dominance and constraints on the parameter space. Finally, we consider the role of $$H \rightarrow \mu \mu $$ decays (and other flavour conserving Higgs decays), as well as precision observables in probing this class of models at future colliders.

France

A. Darricau

H. Lee

J. Orloff

A. Teixeira

Flavour and precision probes of a class of scotogenic models

We determine the average state and the uncorrelated modes that characterize the event-by-event fluctuations of the initial state in two typical centrality classes of Pb–Pb collisions at 5.02 TeV. We find that modes in a narrow central bin are similar to those in events at fixed vanishing impact parameter, while those in a mid-peripheral centrality class are affected by the impact-parameter variation. We study how each fluctuation mode affects observables both in the initial state and in the final state of the collisions, at the end of a state-of-the-art boost-invariant hybrid evolution with KøMPøST + + iSS + SMASH, and show that implementing a hadronic transport cascade in such a mode-by-mode analysis with reasonable statistical noise is costly but feasible.

Renata Krupczak

Nicolas Borghini

United States

Hendrik Roch

Mode-by-mode evolution of Pb–Pb collisions at 5.02 TeV in a hybrid model

We develop and test a spectral-density analysis method, based on the introduction of smeared energy kernels, to extract physical information from two-point correlation functions computed numerically in lattice field theory. We apply it to a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>p</mi><mo stretchy="false">(</mo><mn>4</mn><mo stretchy="false">)</mo></math> gauge theory with fermion matter fields transforming in distinct representations, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi mathvariant="normal">f</mi></msub><mo>=</mo><mn>2</mn></math> Dirac fermions in the fundamental and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mtext>as</mtext></msub><mo>=</mo><mn>3</mn></math> in the 2-index antisymmetric representation. The corresponding continuum theory provides the minimal candidate model for a composite Higgs boson with partial top compositeness. We consider a broad class of composite operators, that source flavored mesons and (chimera) baryons, for several finite choices of lattice bare parameters. For the chimera baryons, which include candidate top-quark partners, we provide the first measurements, obtained with dynamical fermions, of the ground state and the lowest excited state masses, in all channels of spin, isospin, and parity. We also measure matrix elements and overlap factors, that are important to realize viable models of partial top compositeness, by implementing an innovative way of extracting this information from the spectral densities. For the mesons, among which the pseudoscalars can be reinterpreted to provide an extension of the Higgs sector of the Standard Model of particle physics, our measurements of the renormalized matrix elements and decay constants are new results. We complement them with an update of existing measurements of the meson masses, obtained with higher statistics and improved analysis. The analysis software is made publicly available, and can be used in other lattice studies, including application to quantum chromodynamics.

United Kingdom

Ed Bennett

Luigi Del Debbio

Niccolò Forzano

Ryan C. Hill

South Korea

Deog Ki Hong

Japan

Taiwan

Ho Hsiao

Jong-Wan Lee

C.J. David Lin

Biagio Lucini

Alessandro Lupo

Maurizio Piai

Davide Vadacchino

Fabian Zierler

Chimera baryons and mesons on the lattice: A spectral density analysis

In this article, we extend the horizon brightened acceleration radiation (HBAR) framework, originally introduced by Marlan Scully et al. in [Proceedings of the National Academy of Sciences Vol. 115, pp. 8131 (2018)], to the causal diamond (CD) spacetime. We study a cloud of two-level atoms, injected at random times in the asymptotic past of the CD, freely falling toward its causal horizon and emitting scalar radiation via a weak dipole coupling to a quantum field. In the near-horizon region, an emergent conformal symmetry—captured by conformal quantum mechanics (CQM)—governs the field dynamics and allows analytic control of the emission process. We find that the radiation spectrum is thermal, with temperature <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mi>D</mi></msub><mo>=</mo><mn>1</mn><mo>/</mo><mo stretchy="false">(</mo><mi>π</mi><mi>α</mi><mo stretchy="false">)</mo></math>, and that the associated von Neumann entropy flux reproduces the entropy production of the radiation field. These results demonstrate that the causal horizons of the CD spacetime effectively act as a topological thermal reservoir, with thermal properties arising entirely from the global causal structure rather than from underlying microscopic degrees of freedom, highlighting that the validity of the HBAR framework is fundamentally tied to the existence of causal horizons, independent of the presence of a black hole.

Nada Eissa

Carlos R. Ordóñez

Gustavo Valdivia-Mera

Horizon brightened acceleration radiation entropy in causal diamond geometry: A near-horizon perspective