We present , an open-source -based software package designed to simulate cosmological data and perform data-driven inference using a range of modern statistical and machine learning techniques. Motivated by the growing complexity of cosmological models and the emergence of observational tensions, provides a standardized and flexible framework for benchmarking cosmological inference methods. The package supports realistic noise modeling for key observables in the late Universe, including cosmic chronometers, supernovae Ia, baryon acoustic oscillations, redshift space distortions, and gravitational wave bright sirens. We demonstrate the internal consistency of the simulated data with the input cosmology via residuals and parameter recovery using a fiducial $\textit{w}$CDM model. Built-in learning and inference modules include traditional Markov Chain Monte Carlo, as well as more recent approaches such as genetic algorithms, Gaussian processes, Bayesian ridge regression, and artificial neural networks. These methods are implemented in a modular and extensible architecture designed to facilitate comparisons across inference strategies in a common pipeline. By providing a flexible and transparent simulation and learning environment, supports both educational and research efforts at the intersection of cosmology, statistics, and machine learning.

South Korea

Germany

Reginald Bernardo

Chile

Daniela Grandón

Malta

Jackson Levi Said

Víctor Cárdenas

Philippines

Gene Belinario

Reinabelle Reyes

Cosmo-learn: code for learning cosmology using different methods and mock data

An attempt is made to present the effect of the exclusive decay of ZZ/WW gauge bosons at high energy colliders in the Randall–Sundrum (RS) model. In this paper, we investigate the $$l^{-}l^{+}\nu \overline{\nu }$$ final state at muon-TeV colliders through the exclusive decay of ZZ/WW gauge bosons in detail. The result shows that with fixed collision energies, cross-sections for $$l^{-}l^{+}\nu \overline{\nu }$$ production in final state depend strongly on the parameters of the unparticle physics, muon polarization coefficients, parameters on anomalous couplings and also KK-graviton propagators. With the benchmark background $$(\Lambda _{U}, d_{U}) = (1~\text {TeV}, 1.9),$$ the total cross-sections achieve the maximum value when both of muon beams polarize left or right. In case of the different polarization, the cross-section increases as the collision energy increases. The numerical evaluation shows that the cross-section for $$l^{-}l^{+}\nu \overline{\nu }$$ final state through the exclusive decay of WW charged bosons is much larger than that of ZZ neutral bosons under the same conditions. With the contribution of new physics in the RS model, the effect is greatly enhanced and the cross-sections for the production of $$l^{-}l^{+}\nu \overline{\nu }$$ final state can be measured in the future muon collisions.

Vietnam

Bui Giang

Dang Soa

Investigation of the $$l^{-}l^{+}\nu \overline{\nu }$$ final state at multi-TeV muon colliders through the exclusive decay of ZZ/WW gauge bosons in the Randall–Sundrum model

It is well known that in torsion theories, constant fermion condensates may create axial currents in vacuum. Here, we show that domain walls in Einstein–Cartan (EC) gravity induce weak torsion couplings on the order of $$10^{-4}$$ from a magnetic field of $$10^{-9} \,Gauss$$ and an axial torsion of $$10^{-32}\,GeV$$ . An example is given where gravitational waves (GWs) induced by teleparallel oscillations of a double cosmic wall system are generated between fermion condensates around a domain wall with external magnetic and torsion fields, and we find that the domain wall thickness depends on torsion. In the case of a thin domain wall, the torsion is proportional to the external magnetic field at the domain wall. This implies that the external torsion of the domain wall helps to polarize the magnetic moments or spins in EC gravity, a process similar to one that was shown recently by the author (Annals of Phys, 2021). Dark energy is considered to be confined between two teleparallel domain walls. The surface density of domain walls decreases with strong spin–torsion density. A fermion condensate with matching EC conditions is given. When two cosmic double walls coalesce, we obtain a constraint between axial torsion and magnetic fields which determines the coupling torsion $$g_{T}$$ . For zero modes, $$k=0$$ and the fermion condensate is constant, when using the constraints between magnetic and torsion fields. A simple cosmological solution can be obtained from the Aliberti and Lambiase solutions within the Einstein–Cartan–Holst framework by calculating the Barbrro–Immirzi parameter $$\beta \rightarrow {\infty }$$ .

Croatia

Brazil

L. Andrade

Einstein–Cartan fermion condensates trapped in double walls induce axial torsion coupling bounds

In the present work, we studied the $$T_{\bar{c}\bar{s}1}^f(2750)$$ state production through the meson loop mechanism in the $$B^+$$ meson decays, where $$T_{\bar{c}\bar{s}1}^f(2750)$$ is considered as a $$\bar{D}K^*$$ molecular state with $$J^P=1^+$$ . By employing the effective Lagrangian approach, we estimated the branching ratio of the $$B^+ \rightarrow D^+ T_{\bar{c}\bar{s}1}^{f}(2750)$$ and $$B^+ \rightarrow D^{*+} T_{\bar{c}\bar{s}1}^f(2750)$$ processes and found them to be on the order of $$10^{-5}\sim 10^{-4}$$ . The fit fraction of $$T_{\bar{c}\bar{s}1}^f(2750)$$ in different processes was also estimated. We propose to search for $$T_{\bar{c}\bar{s}1}^f(2750)$$ in the $$B^+ \rightarrow D^{*+}\bar{D}^{*-}K^+$$ process, which should be accessible to the Belle II and LHCb Collaborations.

China

Zhuo Yu

Qi Wu

Zi-Li Yue

Dian-Yong Chen

$$T_{\bar{c}\bar{s}1}^f(2750)$$ production in the $$B^+$$ decays processes

We investigate the combined effects of rotation and finite quark chemical potential on inhomogeneous chiral condensation and the chiral phase diagram within the soft-wall holographic QCD model. Using the five-dimensional AdS-RN metric, we study the spatial profile of the chiral condensate and the resulting $$T - \Omega $$ phase diagram under Neumann and Dirichlet boundary conditions. Increasing $$\Omega $$ induces strong spatial inhomogeneity: the condensate is suppressed more strongly near the edge than at the center, and vanishes at the boundary when $$\Omega $$ exceeds a critical value. The chemical potential $$\mu $$ acts as a global suppression factor, reducing the condensate magnitude without altering the spatial pattern. The $$T - \Omega $$ phase diagrams are investigated for different chemical potentials. For the case $$\mu $$ = 0, they are also studied at different distances from the rotation axis. It is found that both $$\Omega $$ and $$\mu $$ lower the chiral phase transition temperature, and their suppression effects are additive. In a rotating system, the critical temperature becomes position-dependent, decreasing with increasing distance from the rotation axis. These findings reveal a rich, spatially dependent phase structure in rotating QCD matter, relevant for non-central heavy-ion collisions.

De-Yang Long

Sheng-Qin Feng

Chiral condensation and chiral phase diagram under combined rotation and chemical potential in holographic QCD

We present a class of exact, dynamical, and fully analytic solutions describing regular black holes formed via the gravitational collapse of matter obeying a generalized polytropic equation of state. Starting from a Vaidya-type geometry with a radially dependent mass function, we demonstrate that regularization of the Kiselev solutions can be achieved through a physically motivated modification of the energy density profile. This procedure leads to nonsingular spacetimes with a de Sitter core and finite curvature invariants at the center. We show that the resulting matter content is naturally described by a generalized polytropic equation of state of the form $$P=\alpha \rho -\zeta \rho ^{\gamma }$$ , where the polytropic index $$\gamma $$ is uniquely determined by the regularization scheme. Within this framework, we obtain exact dynamical generalizations of several well-known regular black hole solutions, including the Hayward and Bardeen spacetimes, as particular cases corresponding to specific values of the polytropic parameters. Remarkably, the requirement that the equation of state remains coordinate independent imposes a universal constraint relating the regularization scale to the mass function, which in turn guarantees the existence of a regular de Sitter core with a curvature scale independent of the black hole mass. Our results provide a unified analytic description of Hayward-like and Bardeen-like black holes emerging from gravitational collapse, offering a consistent effective-matter interpretation rooted in generalized polytropic matter.

Russia

Dmitriy Kudryavcev

Yi Ling

Azerbaijan

Vitalii Vertogradov

Exact dynamical regular black holes from generalized polytropic matter

Building upon our previous work, this study extends the analysis to the rotating case and systematically examines the combined effects of magnetic charge, spin, and accretion flow structure on the resulting shadow and photon ring features. We derive the photon geodesics in the rotating Hayward spacetime via a semi-analytical approach and perform detailed ray-tracing simulations under both spherical and geometrically thin disk accretion scenarios. Our results demonstrate that the presence of magnetic charge induces significant deformations in the black hole (BH) shadow, most notably the emergence of a characteristic D-shaped asymmetry at high spin values and large inclination angles. Furthermore, we analyze the redshift and intensity distributions associated with both prograde and retrograde accretion disks, revealing that the observed image morphology is strongly influenced by relativistic Doppler boosting, gravitational redshift, and frame-dragging effects. Remarkably, the predicted brightness asymmetry and centroid displacement of the shadow images are in good agreement with current VLBI observations, such as those of M87 $$^{*}$$ . These findings underscore the potential of BH shadow imaging as a powerful probe of deviations from the classical Kerr geometry and offer theoretical guidance for interpreting future high-resolution observations.

Sen Guo

En-Wei Liang

Wen-Hao Deng

Qing-Quan Jiang

Yu Liang

Kai Lin

Li-Fang Li

Modeling the shadow and ring structures of rotating Hayward black holes under magnetic charge and accretion influences

We investigate the production of millicharged particles (mCPs) by the Schwinger mechanism in thunderstorms in the atmospheres of different planets in the Solar system. We consider a thundercloud as a giant capacitor that can be discharged in two ways: either by lightnings or by mCP production. Taking into account the observation of lightning strikes, we establish the constraints on the charge and mass of mCPs. We examine two types of cloud configurations: a simple arrangement of two clouds, and a more complex layered structure that gives rise to potential wells. In the latter case, we take into account the effects of Bose enhancement for scalar mCPs, and Pauli blocking for fermionic ones. We use the observational data of planetary atmospheres obtained by satellite missions to establish constraints on the charge and mass of mCP particles. The best constraints came from the observation of thunderstorms in Saturn’s atmosphere under an assumption of layered cloud structure: we obtain a lower limit on the charge of $$10^{-24}$$ for bosonic mCPs. These constraints for bosons are, to the best of our knowledge, the best in the literature.

Ekaterina Dmitrieva

Petr Satunin

Constraints on millicharged particles from thunderstorms on the Solar system planets

We investigate scalar quasinormal modes of a Kerr black hole immersed in a King-type cored dark matter halo within the slow-rotation approximation. Starting from a static King density profile, we construct the rotating spacetime via the Newman–Janis algorithm and derive the effective potential. The quasinormal mode frequencies are computed using the WKB approximation up to sixth order.We find that both the black hole spin and the dark matter halo significantly modify the quasinormal spectrum. The halo deforms the effective potential, shifting its peak and changing its height and width, leading to corrections in both the real and imaginary parts of the frequencies. Rotation introduces an $\textit{m}$-dependent splitting via frame-dragging, while the overtone number $\textit{n}$ governs the decay hierarchy.We further perform time-domain simulations and extract the ringdown signal. Multi-mode fitting shows that although the dominant mode is well captured by a single frequency, additional modes are necessary for an accurate description of intermediate and early-time behavior.A comparison of different WKB orders shows good convergence for low-lying modes, with the sixth-order approximation providing stable results for the fundamental mode and first overtone. A Fisher matrix analysis indicates that the spin and halo density can be tightly constrained, while the halo scale parameter suffers from larger uncertainties due to degeneracies.Our results suggest that dark matter halos leave observable imprints on quasinormal mode spectra and gravitational wave signals, offering a potential probe for future space-based detectors such as LISA.

Yu Wang

Meilin Liu

Haiguang Xu

Quasinormal modes of a Kerr black hole embedded in a King-type cored dark matter halo

We study the evolution of cosmological density perturbations in massive conformal gravity (MCG). We show that conformal fermionic matter alone does not generate growing density perturbations in the subhorizon regime. By introducing a conformally coupled scalar field, however, an effective cold dark matter component emerges at the effective level. The resulting coupled perturbation equations admit growing solutions with a stronger effective gravitational interaction, allowing cosmic structure formation in MCG and potentially favoring earlier structure formation at high redshifts.

F. Faria

G. Silva

Cosmic structure formation in massive conformal gravity