Stereoscopic fluorescent observations by the High Resolution Fly's Eye detector revealed correlations between arrival directions of ultra-high-energy cosmic rays and positions of distant BL Lac type objects (Gorbunov et al. 2004, Abbasi et al. 2005). They implied the existence of non-deflected particles travelling for cosmological distances, hard to explain within standard physics and...
The numerical calculation of observables in quantum theory is reduced to the sampling from a set of random variables with a joint distribution density defined analytically on the basis of physical theory. This problem is solved by various modifications of the Metropolis method, but it requires significant computational costs with a large sample size and the number of random variables...
The experimental discovery of resonant-like states in the di-J/psi mass spectra in pp-collisions near the production threshold suggests the existence of fully-charmed tetraquarks (broad structure at 6600 MeV and narrow structures at 6900 and 7200 MeV). Numerous theoretical models following this discovery provide descriptions of the observed data, propose mechanisms underlying formation of this...
Axion-like particles (ALPs) are a class of hypothetical bosons beyond the standard model of particle physis, which are
very weakly-interacting and long- lived. Since many ALPs may be produced in hot plasma in supernovae (SNe), a nearby
SNe Ia can be used as a probe of ALPs. It is desirable to predict the ALP emission from SNe Ia to discuss a possible
constraint that can be obtained from the...
To achieve enhanced precision in neutrino analysis, it is crucial to consider the kinematic distributions of reaction products. This poster will showcase methods for reconstructing the momentum of charged pions within the novel neutrino detector SuperFGD of the T2K experiment. Additionally, comparisons will be presented between the developed statistical and machine learning approaches.
In this work, we show that quantum corrections to some cosmological models [1] can lead to a significant modification of the behaviour of the initial potential and the appearance of a non-zero ground state energy of the Universe which can be interpreted as a cosmological constant.
We apply the formalism of the effective potential to the simplest forms of $\alpha$-attractors which can be...
The TAIGA astrophysical complex [1], located in the Tunka Valley, 50 km from Lake Baikal, was developed for research in the field of ultra-high-energy gamma-ray astronomy and cosmic ray physics. This report provides a detailed description of the methodology for detecting gamma rays using the TAIGA-IACT atmospheric Cherenkov telescopes in stereo mode [2] and presents the results obtained from...
Employing the publicly available CosmoLattice code, we conduct numerical simulations of a domain wall network and the resulting gravitational waves (GWs) in a radiation-dominated Universe in the $Z_2$-symmetric scalar field model. In particular, the domain wall evolution is investigated in detail both before and after reaching the scaling regime, using the combination of numerical and...
The main source of information about high-energy cosmic rays (above 1015 eV) are extensive air showers (EAS), which are formed as a result of interaction of primary cosmic rays (PCR) with nuclei of atmospheric atom. In the energy range from 1015 to 1017 eV the PCR energy spectrum, reconstructed by the data of EAS experiments, has features which cannot be explained within the frameworks of...
NOvA is a long-baseline accelerator-based neutrino oscillation experiment designed to measure electron (anti-)neutrino appearance and muon (anti-)neutrino disappearance. The experiment employs a 297t near detector at Fermilab and a larger 14kt far detector in Minnesota, both are tracking calorimeters filled with liquid scintillator. Event selection in NOvA is crucial for distinguishing...
The NOvA experiment, primarily focused on neutrino oscillation studies, also provides a unique platform to search for exotic and non-standard physics phenomena. In this poster, we present the ongoing analyses in the following topics: atmospheric and cosmogenic neutrinos, slow magnetic monopoles, high-energy muons, low-ionizing particles, neutron-antineutron oscillation. We will outline the...
Extensive air showers (EAS), produced by cosmic rays in the atmosphere, serve as probes of particle interactions, providing access to energies and kinematical regimes beyond the reach of laboratory experiments. Measurements from multiple cosmic-ray detectors indicate a significant, yet unexplained, discrepancy between the observed muon content in EAS and that predicted by state-of-the-art...
We present a stable cosmological model of a closed universe in the presence of conventional scalar
field. The stability of the model and the absence of singularity is ensured by spatial curvature
without the need for additional peculiar matter. We reconstruct the Lagrangian and numerically
compute observational predictions, including the number of e-folds, the spectral index $n_s$, and...
About 1% of solar neutrinos are produced in the CNO cycle. Despite their subdominant role in the energy production, CNO neutrinos provide important information on the abundance of heavy elements in the solar core. In this work we present the details of the final analysis of Borexino data for measuring the flux of solar CNO neutrinos. This analysis features the fit of the electron recoil...
Young compact clusters of massive stars contain dozens of O-, B- and WR-type stars with fast powerful winds in a small $\sim$ pc radius. The acceleration of particles by ensembles of shocks and waves of compression and rarefaction in the turbulent environment of young massive star clusters (YMSCs) is an alternative to the standard paradigm of Galactic cosmic rays acceleration on supernova...
Carpet-3 is a detector array for high-energy ($E \geq 100 TeV$) extensive atmospheric shower (EAS) detection. It is situated at geographical coordinates: $43,273^\circ N, 42,685^\circ E$, 1700 m above sea level. It consists of a central part $196 m^2$ in area, an underground muon detector $410 m^2$ in area and 30+ remote registration points.
We have created a model of Carpet-3 using Geant4...
Recent multi-messenger observations suggest that high-energy neutrinos may be produced close to central black holes in active galaxies. These regions may host dark-matter (DM) spikes, where the concentration of DM particles is very high. Here we explore the contribution of the DM annihilation to the target photons for the neutrino production, proton-photon interactions, estimate the associated...
The T2K long-baseline neutrino oscillation experiment is designed to probe CP violation in the neutrino sector and to perform precise measurements of neutrino oscillation parameters. The T2K neutrino beam, produced at J-PARC, is detected by the near detector ND280, located 280 meters downstream from the proton target. The recent upgrade of the ND280 was accomplished to reduce systematic...
We report our results on the new technique for searching for photon-induced EAS events at the Carpet-3 experiment. To search for photon-like events, we employ a neural network, trained on Monte-Carlo simulations of the experiment. On Monte-Carlo simulations our method achieves considerably higher background rejection efficiency than traditional methods, particularly for EAS events with high...
Two-neutrino double electron capture is a rare nuclear decay where two electrons are simultaneously captured from the atomic shells and two neutrinos are carried away.
The measurements of the energies of the emitted particles and the half-life of the 2EC2$\nu$ decay to the ground state are of great interest to nuclear physics. The model predictions for 2EC2$\nu$ half-life are based on the...
We examine the sterile neutrino dark matter production in the primordial plasma with lepton asymmetry. The model parameter space (sterile-active neutrino mixing angle, sterile neutrino mass) is heavily limited by cosmological considerations and astrophysical observations. We argue that, with specifically tuned flavor fractions (electron, muon and tau) of the initial lepton asymmetry, one can ...
SuperNova Early Warning System (SNEWS) is an international network of neutrino experiments, aiming at the real-time search and analysis of neutrino signals for providing the early warning of galactic supernova.
This system has been operating since 1998 in a simple coincidence mode.
In this work we present the current status and plans of an ongoing major upgrade of the SNEWS system, which...
In this paper, we attempt to explain the TeV-PeV neutrinos observed by IceCube by assuming that they originate from active galactic nuclei. The results are obtained in the model where the accretion disk emits in the UV-optical range inside the electron plasma cloud. Using a Monte-Carlo approach to simulate photopion interactions in the jets and then taking into account the cosmological...
