Search Results (266)

Merging galaxy clusters represent one of the most powerful macroscopic laboratories in the Universe for searching for new physics within the dark sector. High-velocity cosmic collisions inherently separate the dark matter and stellar components from the highly collisional, X-ray-emitting intracluster gas. These massive systems provide an ideal environment to probe the fundamental nature of dark matter, specifically testing whether it behaves as a strictly collisionless particle or exhibits non-zero self-interactions. While pioneering systems like the Bullet Cluster historically demonstrated the macroscopic decoupling of dark and ordinary matter, the field has evolved into a sophisticated discipline driven by multi-disciplinary methodologies. This review synthesizes recent theoretical and empirical advances in interpreting post-collision dynamics. It examines how the synergy of combined approaches—integrating multi-wavelength observations from gravitational lensing and X-ray mapping with high-fidelity N-body hydrodynamical simulations—allows the translation of macroscopic spatial observables into stringent constraints on microscopic particle properties. Through this synthesis, the work evaluates how leveraging heterogeneous merger ensembles can reliably advance the ongoing search for physics beyond the standard cosmological model. Full article

Understanding the nature of dark matter (DM) and its detection remains one of the most significant unsolved problems in astroparticle physics and cosmology. Considerable efforts have been devoted to the detection of DM through both direct and indirect approaches. Gamma-ray observations offer a powerful probe for the indirect detection of DM. In particular, the spectral features of gamma rays produced through DM interactions are strongly dependent on the underlying annihilation channels into the Standard Model (SM) particles. In this work, we investigate the role of annihilation branching fractions in determining the $\gamma$-ray emission from dark matter within the framework of the Inert Doublet Model (IDM). The lightest neutral inert scalar, which serves as a viable DM candidate, can annihilate into various SM particles, including fermions, gauge bosons, and Higgs bosons, depending on DM mass and the model parameters. We analyze how the branching fractions into these final states influence the resulting $\gamma$-ray spectra and fluxes. Our study demonstrates that different dominant annihilation channels produce distinct spectral features, significantly affecting the predicted high-energy $\gamma$-ray signals. By examining the dependence of $\gamma$-ray emission on the branching behavior of DM within IDM, we identify regions of parameter space that can provide better experimental constraints while remaining consistent with the relic density requirements. The results highlight the importance of annihilation branching fractions in interpreting indirect detection signals and provide insights into distinguishing DM within IDM from other weakly interacting massive particles (WIMPs) scenarios. This work underscores the potential of $\gamma$-ray observations as a sensitive probe of the IDM parameter space and its underlying annihilation dynamics. Variations in the branching ratios directly influence the resulting $\gamma$-ray spectra, thereby affecting the prospects for indirect search of DM with the ground-based $\gamma$-ray telescopes such as the Major Atmospheric Cherenkov Experiment (MACE). Full article

Relativistic interaction of ultra-intense laser pulses with cluster targets is of particular interest for high-energy-density physics, compact X-ray source development, and laboratory astrophysics. Understanding the dynamics of such plasmas requires precise control of their parameters, in particular temperature, on subpicosecond timescales. In this study, X-ray spectral methods were used to diagnose the laser plasma of krypton cluster targets, created at laser pulse intensities of the order of 10²⁰–10²¹ W/cm². The use of a time-dependent detailed radiation-collisional kinetic model made it possible to describe the results of the observed X-ray spectra in the femtosecond laser plasma of a cluster target. We present a method for diagnosing the non-stationary plasma of high-atomic-number (krypton) clusters using resonance spectral lines 1s²2s²2p⁵3s ¹P₁–1s²2s²2p^{6 1}S₀ and 1s²2s²2p⁵3s ³P₁–1s²2s²2p^{6 1}S₀ of the Ne-like Kr XXVII ion, allowing one to determine the plasma temperature at the moment of “plasma channel” formation. In the experiment, this temperature was shown to be 55 ± 5 eV. The same spectroscopic approach can be extended to other cluster species (for example, Ar, Xe) for non-stationary plasma diagnostics in the relativistic regime. Full article

We review the role of primordial black holes (PBHs) for illuminating the dark ages of the cosmological evolution and as dark matter (DM) candidates. We elucidate the role of phase transitions for primordial black hole formation in the early Universe and focus our attention on the cosmological QCD phase transition within a recent microscopic model. We explore the impact of physics beyond the Standard Model (SM) on the cosmic equation of state and the probability distribution for the formation of PBHs, which serve as candidates for DM and contribute to present-day binary black hole merger events. Full article

We review recent interferometric schemes designed to probe physics beyond the Standard Model through the detection of geometric phases. Within the kinematic approach to non-cyclic geometric phases, we discuss how interactions with hidden-sector degrees of freedom, such as axion-like particles and mirror-matter candidates, can induce potentially observable phase shifts in ordinary fermionic systems. We further show how the same geometric framework can be extended to particle mixing systems and fundamental symmetries, providing a phase-based signature of the Charge–Parity–Time (CPT) violation. These results illustrate how geometric phases can encode information that is not always directly accessible through standard transition probabilities, making quantum interferometry a complementary tool for testing dark-sector interactions, fundamental properties of elementary particles, acceleration-induced quantum-field effects, and phase-based thermometry. We also critically assess the experimental requirements and limitations of the proposed schemes. Full article

The multi-messenger exploration of dark matter and physics beyond the Standard Model has emerged as a central direction in modern astro-particle physics, particularly following the discovery of gravitational waves. In this work, we present a comprehensive review and forward-looking perspective on machine-learning-enhanced multi-messenger approaches, combining information from gravitational waves, cosmic rays, gamma rays, neutrinos, and collider experiments. We summarize the current state of the field, discuss recent methodological developments, and outline a coherent research program aimed at integrating heterogeneous datasets within a unified inference framework. We collaboratively propose a plan for forthcoming analyses aiming at extracting information on the properties and interactions of dark matter, and finally on its genesis, combining multi-messenger astronomy techniques and inputs from laboratory physics. The main objectives planned in this line of research comprise: (i) the multi-messenger analysis of new physics in cosmology, including mainly, but not only, several different models of dark matter; (ii) the phenomenology of new physics signatures in ground-based cosmic rays experiments, with cross-correlation to the corresponding physical, astrophysical and cosmological observations; (iii) the development of machine learning methods for data analysis in ground-based cosmic rays experiments, in light of the new physics signatures. We note that several groups have explored the use of multi-messenger observations, including gravitational waves, to probe alternative dark matter candidates. The present work builds on these developments by focusing on the role of machine learning in integrating heterogeneous datasets. We foresee that a cross-fertilizing approach combining the information that arises from very different experimental methodologies will represent the right and successful path to extract information about the very elusive dark matter particles and provide answers to the main questions that are left in fundamental physics. Full article

This paper presents a further step in the development of scale invariant fully conformal cosmology (FCC), formulated in our previous study. Whereas the previous paper focused mainly on the global cosmological consequences of the fully conformal metric and their confrontation with selected astrophysical data, here we analyze its local gravitational and background consequences. On the background of the fully conformal metric we formulate an effective generalization of the weak Schwarzschild field in the corresponding FCC global coordinates and derive from it the associated modified intensity of the Newtonian central field. We further derive the cosmological state/constitutive equation p = − ε/3 as a direct consequence of the fully conformal metric rather than as an ad hoc additional postulate. Likewise, within the fully conformal metric, spatial flatness and the critical density ρ_crit are understood as direct consequences of this metric structure rather than as independently postulated inputs. From the condition of global equilibrium between negative cosmological pressure and the gravitational cohesive pressure of homogeneously distributed matter, the effective particulate fraction is obtained as β ≈ 0.45 of the total critical density ρ_crit. For the relatively well-confirmed baryonic matter fraction ${\overline{\mathrm{\Omega }}}^{bar} \approx 0.05$, this stable-equilibrium condition then leads to the corresponding particulate fraction of collisionless dark matter ${\overline{\mathrm{\Omega }}}_{FCC}^{dm} \approx 0.40$, which is in principle determined by the global cosmological equilibrium within this framework. Because direct identification of the entire dark fraction with standard collisionless cold dark matter would very probably be incompatible with the main structural observables, we discuss an effective phenomenological decomposition into a structuring cold dark matter component (cdm) and an almost homogeneous residual warm-dark-matter-like component (wdm). In this interpretation, the paper preserves the previously introduced global FCC framework while simultaneously providing a concrete background prediction for the matter content and a physically motivated basis for further testing of structure formation within scale invariant fully conformal cosmology. Full article

Dwarf galaxies, although intrinsically faint and containing only modest stellar populations, provide an unusually sensitive testing ground for understanding how structure emerges in a cosmological context. Their shallow gravitational potentials make them particularly responsive to environmental influences and internal feedback, allowing researchers to probe physical processes that are harder to isolate in larger systems. Over the past decade, advances in numerical modeling—ranging from finely resolved hydrodynamic calculations to large-volume N-body suites—have offered increasingly detailed views of their kinematic evolution, star formation cycles, and dark matter configurations. Modern simulations now reproduce several of the empirical relationships observed in nearby dwarfs, including trends connecting mass, size, chemical enrichment, and luminosity. However, uncertainties in how feedback is implemented still produce noticeable variation among models. A long-standing tension involves the predicted shape of central dark matter profiles. Many simulations generate steep cusps, even though observations frequently point to shallower cores. Energetic stellar activity has been proposed as a mechanism for reshaping these regions, yet its effectiveness depends sensitively on resolution and feedback prescriptions. Another unresolved issue concerns the unexpectedly small number of known satellites in the Local Group compared with the abundance of low-mass halos in ΛCDM predictions. Recent work indicates that many such halos may host extremely faint systems that elude current surveys. Large simulation programs such as FIRE, APOSTLE, and NIHAO pursue these questions with differing assumptions and numerical strategies. Each captures certain aspects of dwarf galaxy evolution, but none fully replicates the diversity seen observationally. Considering results from multiple frameworks remains essential for constructing a comprehensive picture of how these small galaxies form, evolve, and interact with their environments. Full article

Given recent advancements in dark matter (DM) search experiments, particularly the latest LUX-ZEPLIN (LZ) direct detection (DD) results, we systematically investigate the light bino–higgsino DM scenario within the natural supersymmetric framework. Requiring the electroweak fine-tuning parameter ${\Delta }_{\mathrm{EW}}<30$ fixes the higgsino mass parameter in the range of $\left|\mu \right|\in [100,350]$ GeV, while we extend the bino mass to $M_1\in [10,350]$ GeV. Incorporating constraints from Higgs physics, rare B decays, LEP limits, and DD experiments, we find that part of the parameter space remains viable. However, the relic density of neutralino DM necessarily lies below the observed Planck value, contributing at most ∼2% of the total DM abundance. Some of the surviving parameter space is already excluded by current 13 TeV LHC searches, while the future 14 TeV HL-LHC with 3000 fb⁻¹ luminosity will probe the remaining region of the considered parameter space. Full article

We investigate the possibility of testing the Cosmological Principle within a specific axisymmetric metric. Starting from the Einstein field equations, we derive a perturbed form of the Friedmann equation based on this metric and obtain a generalized form for matter density perturbations. By combining these, we establish the relationship between the scale factor a and the terms for matter density and dark energy over time. We then use the Union2.1 and PantheonPlus Type Ia supernovae datasets and CMB shift parameter R to constrain the perturbation parameters introduced in the model. This analysis allows us to assess whether matter perturbation could lead to observable inhomogeneity in cosmic expansion. Finally, we summarize the key parameters used in the calculation and discuss their physical significance. Our results indicate that within this axisymmetric metric, the contribution of matter perturbations to cosmic anisotropy and inhomogeneity is negligible, posing no challenge to the Cosmological Principle. Full article

Noble liquids, notably argon and xenon, are utilised as both detector media and as the detector target for dark matter and neutrino physics experiments. When the noble liquid is excited by particles, it scintillates vacuum ultraviolet light, which sensors then detect. A major focus of the detector development community is on producing precision light sensors for noble liquid detectors. We introduce a flash lamp to test VUV-sensitive light sensors with light at wavelengths observed using noble liquid detectors. This paper discusses the design and presents results from a flash lamp prototype operated at room temperature. Full article

This manuscript investigates conformal $\eta$-Ricci–Yamabe solitons of type $(\kappa ,l)$ on Kählerian Norden space-time admitting a Kählerian Norden torse-forming vector field. Necessary conditions are obtained under which the soliton exhibits expanding, steady, or shrinking behavior. The analysis is further extended to several physically relevant fluid models, including dark fluid, dust fluid, stiff matter, and radiational fluid, and the corresponding geometric constraints are derived. In addition, structural results are established for Kählerian Norden space-times with a vanishing space–matter tensor and with a divergence-free matter tensor, highlighting their influence on the curvature geometry. The study also addresses several intrinsic curvature conditions of the space-time, such as conformal flatness, Ricci semi-symmetry, Ricci recurrence, and pseudo-Ricci symmetry, leading to a collection of geometric and physical characterizations. The results obtained provide a unified geometric framework linking Ricci–Yamabe soliton structures, fluid dynamics, and curvature properties within the setting of Kählerian Norden geometry. Full article

The nucleon spin–orbit interaction is a cornerstone of nuclear structure theory, yet its isospin dependence remains insufficiently constrained within modern nuclear energy density functional (EDF) theory. It was recently shown that, within the framework of extended Skyrme EDFs, the charge-weak form factor difference $\Delta F_{\mathrm{CW}}$ in ⁴⁸Ca exhibits remarkable sensitivity to the effective isovector spin–orbit (IVSO) interaction, whereas $\Delta F_{\mathrm{CW}}$ in ²⁰⁸Pb is much less sensitive to this channel. Extending this analysis to other nuclei, we find that ⁹⁰Zr, with its ten spin–orbit unpaired $1{\mathrm{g}}_{9/2}$ neutrons, displays a $\Delta F_{\mathrm{CW}}$ sensitivity to the IVSO strength similar to that of ⁴⁸Ca, arising from modifications to the central mean-field potential rather than the one-body spin–orbit potential. In contrast, ⁶²Ni, like ²⁰⁸Pb, remains largely insensitive to the IVSO interaction. This structure-driven distinction suggests an experimental strategy: future parity-violating electron scattering measurements, e.g., the MREX experiment at the MESA facility, on ⁴⁸Ca and ⁹⁰Zr would help constrain the effective IVSO strength, while measurements on ²⁰⁸Pb and ⁶²Ni can provide a cleaner probe of the density dependence of the symmetry energy with reduced IVSO sensitivity. Full article

This study proposes a methodological framework for extending Malware Information Sharing Platform (MISP) taxonomies in the domain of Dark Web drug forums through the integration of large language models (LLMs) and Human-in-the-Loop (HITL) validation. The research addresses the existing ontological gap between traditional MISP taxonomies, focused on technical or chemical indicators, and the linguistic and morphological complexity of illicit digital markets. By modelling the primary physical form as an ontological predicate with mutually exclusive values (for example, powder, pill–tablet–capsule, liquid, and plant-matter), the proposed approach captures the material dimension of the discourse, enhancing semantic disambiguation and forensic traceability. The Mistral 7B model was used in the morphology-classification stage conducted on a stratified analytical subset of 2904 drug-related Dark Web posts, extracted from a final corpus of 6456 posts after data cleaning and relevance filtering. In the first pass, 76.48% of posts were directly assigned to one of the base morphological categories, while 23.52% were labelled as unclear and subsequently reviewed through the HITL stage. Following HITL refinement and full reclassification, the proportion of posts labelled as unclear decreased from 23.52% to 11.29%, corresponding to a 51.99% relative reduction in ambiguity. Network visualisation with VOSviewer revealed three major discursive axes—recreational–commercial, pharmaceutical–opioid, and transnational–logistical—reflecting the hybrid semantic structure of digital drug markets. The results show that combining LLM-based inference with expert oversight improves the interpretability, reproducibility and ontological robustness of cyberintelligence models, offering a replicable framework for other sensitive domains such as terrorism or child exploitation. Full article