Gravitational lensing caused by the gravitational field of massive objects has been studied and acknowledged for a long period of time. In this paper, however, we propose a different mechanism where the bending of light stems from the non-linear interaction of gravitational, electromagnetic and axion waves that creates the high curvature zone in the space-time fabric. The striking distinction in the

Baryon asymmetry via non-thermal leptogenesis is explained in the framework of the standard Coleman-Weinberg inflationary model. The CP-violation asymmetry factor arises from the out-of-equilibrium decays of heavy right-handed neutrinos in supersymmetric SO(10) GUT models. All quantities of interest are computed in terms of the two parameters of the inflationary potential, namely the vacuum expectation

Microquasars (MQs) are binary systems composed by a star feeding mass to a compact object through an accretion disk. The compact object, usually a black hole, launches oppositely directed jets which are typically observed in our galaxy through their broadband electromagnetic emission. These jets are considered potential galactic neutrino sources. MQs can also have been formed by the first generations

The VERITAS array is a set of four imaging atmospheric Cherenkov telescopes (IACTs) sensitive to gamma rays with energies above 80 GeV. Each telescope is based on a tessellated mirror, 12 metres in diameter, which reflects light from a gamma-ray-induced air shower to form an image on a pixellated ‘camera’ comprising 499 photomultiplier tubes. The image brightness is the primary measure of the gamma

Tau neutrinos with energies in the PeV-EeV range produce up-going extensive air showers (UEAS) if they interact underground close enough to the surface of the Earth. This work studies detectability of the UEAS with a system of fluorescence telescopes overlooking dark, low reflectivity, area on the ground up to the distances 20–50 km from mountain top(s). Such system could provide sensitivity sufficient

Prescriptions for electron injection into the diffusive shock acceleration process are required in many practical considerations of cosmic-ray astrophysics, particularly in modeling of the synchrotron emission of astrophysical sources. In particle-in-cell simulations of quasi-parallel magnetized collisionless shocks, we analyse the evolution of particle spectra. We find that in the later stages of

Low-energy neutrinos are clean messengers from supernovae explosions and probably carry unique insights into the process of stellar evolution. We estimate the expected number of events considering coherent elastic scattering of neutrinos off silicon nuclei, as would happen in Charge Coupled Devices (CCD) detectors. The number of expected events, integrated over a window of about 18 s, is ∼4 if we assume

During the era of primordial nucleosynthesis the background of non-equilibrium antineutrinos is being formed due to decays of neutrons and nuclei of tritium. The spectra of antineutrinos of this background were calculated taking into account the Coulomb interaction between electron and daughter nucleus in β−decay. The dependence of these spectra on the value of the baryon-to-photon ratio η at the period

The origin and nature of the cosmic rays is still uncertain. However, a big progress has been achieved in recent years due to the good quality data provided by current and recent cosmic-rays observatories. The cosmic ray flux decreases very fast with energy in such a way that for energies ≳1015 eV, the study of these very energetic particles is performed by using ground based detectors. These detectors

We present a new approach for the identification of ultra-high energy cosmic rays from sources using dynamic graph convolutional neural networks. These networks are designed to handle sparsely arranged objects and to exploit their short- and long-range correlations. Our method searches for patterns in the arrival directions of cosmic rays, which are expected to result from coherent deflections in cosmic

Several experiments have been conducted in the YangYang Underground Laboratory in the Republic of Korea such as the search for dark matter and the search for neutrinoless double beta decay, which require an extremely low background event rate due to the detector system and the environment. In underground experiments, neutrons have been identified as one of the background sources. The neutron flux in

We present an updated estimate of the cosmic radio background (CRB) and the corresponding attenuation lengths for ultra-high energy photons. This new estimate provides associated uncertainties as a function of frequency derived from observational constraints on key physical parameters. We also present the expected variation in the spectrum of the CRB as a function of these parameters, as well as accounting

XL-Calibur is a hard X-ray (15-80 keV) polarimetry mission operating from a stabilised balloon-borne platform in the stratosphere. It builds on heritage from the X-Calibur mission, which observed the accreting neutron star GX 301 - 2 from Antarctica, between December 29th 2018 and January 1st 2019. The XL-Calibur design incorporates an X-ray mirror, which focusses X-rays onto a polarimeter comprising

The theory termed ‘special relativity (SR) with a preferred frame’ incorporates the preferred frame into special relativity while retaining the fundamental space-time symmetry which, in the standard SR, manifests itself as Lorentz invariance. In this paper, the theory is extended to particle dynamics based on the concept of the ‘modified spacetime symmetry’ which allows to develop the theory along

We develop a general formalism to treat reflection of spherical electromagnetic waves or, more precisely, dipole radiation from a spherical surface. Our main objective is interpretation of radio wave signals produced by cosmic ray interactions with Earth’s atmosphere which are observed by the Antarctica based ANITA detector after reflection off the ice surface. The incident wave is decomposed into

This work explains a delayed-coincidence method to perform MeV-scale neutrino spectroscopy with electron-neutrino capture on gallium. An electron-neutrino possessing energy greater than 407.6 keV can be captured on gallium and produce a daughter germanium nucleus at its first excited state with a mean lifetime of 114 ns. The released electron and gammas before the first excited state of Ge can generate

The surface 210Pb is one of the main background sources for dark-matter-search experiments using NaI(Tl) crystals, and its spectral features associated with the beta-decay events for energies less than 60 keV depends on the depth distribution of 210Pb in the surface of an NaI(Tl) crystal. Therefore, we must understand the profile of surface 210Pb to precisely model the background measurement in the

We review the general construction of distribution functions for gases of fermions and bosons (photons), emphasizing the similarities and differences between both cases. The central object which describes polarization for photons is a tensor-valued distribution function, whereas for fermions it is a vector-valued one. The collision terms of Boltzmann equations for fermions and bosons also possess the

In R-parity violating supersymmetry, the gravitino as the lightest supersymmetric particle (LSP) is a good candidate for dark matter, with the interesting characteristic to be detectable through γ-ray telescopes. We extend this analysis considering an axino next-to-LSP (NLSP) as a coexisting dark matter particle contributing with a detectable signal in the γ-ray spectrum. The analysis is carried out

We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos (ν¯e) are detected in an organic liquid scintillator through the inverse β-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8–16.8 MeV on neutrino fluxes from unknown

We re-examine the longstanding disagreement between the SIMPLE and PICASSO superheated liquid-based dark matter search projects regarding discrimination between neutron- and α-induced bubble nucleation events, and its dependence on the distribution of liquid droplet sizes. A simple analysis based on (1) the interaction of α and neutrons with the detector droplet size distribution, combined with (2)

In the standard model of cosmology, Cosmic Microwave Background (CMB) sky is expected to preserve spatial symmetries. Following our previous studies, we search for evidence of a parity preference in the latest full-mission CMB temperature maps from ESA’s Planck probe. Specifically, we probe (a)symmetry in power between even and odd multipoles of CMB, that corresponds to a particular parity preference

A method is proposed to reconstruct the depth at which showers reach the maximum number of charged particles (Xmaxcharged) using atmospheric Cherenkov telescopes. The dependence of the Cherenkov signal with telescope distance from shower core is explored and a region in which the measurement is possible is determined (150 to 200 m). A parametrization is presented to reconstruct Xmaxcharged. The resolution

The Fermi–LAT telescope has measured the extragalactic gamma–ray background (EGB) generated by the ensemble of all extragalactic sources. The energy distribution of the EGB is well described as a power–law with a spectral index approximately equal to 2.3, and an exponential cutoff, that is consistent with being the effect of absorption of high energy photons assuming an emission that is an unbroken

Employing large thunderstorm ground enhancements (TGEs) as a manifestation of the strong electric field in thundercloud we measure fluxes of almost all species of secondary cosmic rays to estimate the strength of the intracloud electric field. The modulation that electric field poses on charged particle flux gives a sizable change in count rate of detectors measuring high energy muon flux and inclined

The dynamics of massive particles near the horizons of charged rotating and charged accelerating black holes is studied. This is done, in particular, from the point of view of studying the screening effect of Hawking radiation and shielding of the Penrose process for these two black holes. We do this by identifying the forbidden regions which are the regions where the particles have negative kinetic

Low energy cosmic rays are modulated by the solar activity when they propagation in the heliosphere, leading to ambiguities in understanding their acceleration at sources and propagation in the Milky Way. By means of the precise measurements of the e−, e+, e−+e+, and e+/(e−+e+) spectra by AMS-02 near the Earth, as well as the very low energy measurements of the e−+e+ fluxes by Voyager-1 far away from

Although supernova remnants remain the main suspects as sources of Galactic cosmic rays up to the knee, the supernova paradigm still has many loose ends. The weakest point in this construction is the possibility that individual supernova remnants can accelerate particles to the rigidity of the knee, ~ 106 GV. This scenario heavily relies upon the possibility to excite current driven non-resonant hybrid

We introduce a new simulation and analysis paradigm for Imaging Atmospheric Cherenkov Telescope (IACT) arrays, simulating the actual observation conditions as well as individual telescope configuration for each observation unit. Compared to existing frameworks, where simulations are usually generated using pre-defined settings, this run-wise simulation approach implies more realistic simulations and

Depending on their type, supernova remnants may have ejecta material with high abundance of heavy elements such as carbon or oxygen. In addition, core-collapse supernovae explode in the wind material of their progenitor star that may also have a high abundance of heavy elements. Hadronic collisions in these enriched media spawn the production of gamma rays, neutrinos, and secondary electrons with spectra

As ultra-high energy photons (EeV and beyond) propagate from their sources of production to Earth, radiation-matter interactions can occur, leading to an effective screening of the incident flux. In this energy domain, photons can undergo e+/e− pair production when interacting with the surrounding geomagnetic field, which in turn can produce a cascade of electromagnetic particles called preshower.

AR Scorpii is a compact binary system which consists of a magnetic white dwarf and an M-type main sequence cool star. This binary system was discovered as a source of pulsating radiation in radio, infrared, optical, ultraviolet and X-ray wavebands. In this work, we have analyzed the γ-ray data in the energy range 100 MeV to 500 GeV from the Fermi-Large Area Telescope (LAT) observations for the period

Within the framework of the modified potential cluster model with a classification of orbital states according to Young diagrams, the possibility of describing experimental data for total cross sections of the neutron radiative capture on 11B to the ground state of 12B at energies of 10 meV (1 meV = 10−3 eV) to 7 MeV was considered. It was shown that, taking into account only the E1 transition from

The LUX-ZEPLIN dark matter search aims to achieve a sensitivity to the WIMP-nucleon spin-independent cross-section down to (1–2)×10−12 pb at a WIMP mass of 40 GeV/c2. This paper describes the simulations framework that, along with radioactivity measurements, was used to support this projection, and also to provide mock data for validating reconstruction and analysis software. Of particular note are

The angular resolution limits achievable for perfect ground-based high-altitude gamma-ray air shower detectors are investigated, to serve as benchmarks for the design of real detectors. A ‘perfect’ detector is assumed to accurately measure impact position, time and energy of all electromagnetic shower particles reaching the ground. The shower direction is determined from a likelihood fit to all measured

The limited knowledge of atmospheric parameters like humidity, pressure, temperature, and the index of refraction has been one of the important systematic uncertainties in reconstructing the depth of the shower maximum from the radio emission of air showers. Current air shower Monte Carlo simulation codes like CORSIKA and the radio plug-in CoREAS use various averaged parameterized atmospheres. However

The H.E.S.S. Galactic Plane Survey [HGPS, 1] represents one of the most sensitive surveys of the Galactic Plane at very high energies (VHE, 0.1 < E < 100 TeV). However the source detection algorithm of the HGPS pipeline is not well-suited for complex regions, including sources with shell-like morphologies. As an alternative and complementary approach, we have investigated blind search methods for VHE

We consider an extension of Higgs inflation in which the Higgs field is non-minimally coupled to gravity through its kinetic term. We analyzed power-law coupling functions with positive or negative integer power and found that the Higgs boson can drive a successful inflation only for the cases n=2,1,0,−1. Theoretical predictions for both tensor to scalar ratio r and scalar spectral index ns are within

The SPHERE-2 balloon-borne detector designed for extensive air shower (EAS) observations using EAS optical Vavilov-Cherenkov radiation (“Cherenkov light”), reflected from the snow-covered surface of Lake Baikal is described. We briefly discuss the concept behind the reflected Cherenkov light method, characterize the conditions at the experimental site and overview the construction of the tethered balloon

At ground level, the azimuthal distribution of muons in inclined Extensive Air Showers (EAS) is asymmetric, mainly due to geometric effects. Several EAS observables sensitive to the primary particle mass, are constructed after mapping the density of secondary particles from the ground plane to the shower plane (perpendicular to the shower axis). A simple orthogonal projection of the muon coordinates

The effective observation time of Imaging Air Cherenkov Telescopes (IACTs) plays an important role in the detection of γ-ray sources, especially when the expected flux is low. This time is strongly limited by the atmospheric conditions. Significant extinction of Cherenkov light caused by the presence of clouds reduces the photon detection rate and also complicates or even makes impossible proper data

In many physical situations, especially in space, plasmas are found to have anisotropic power-law distributions, i.e., they can have one-dimensional Kappa distribution with high-energy tails in a preferred direction and a Maxwellian distribution perpendicular to it. In this work, we have used this distribution to study the Landau damping of electron-acoustic waves (EAWs) in the Kappa–Maxwellian plasma

Recent observations of cosmic ray protons in the energy range 102–105 GeV have revealed that the spectrum cannot be described by a simple power law. A hardening of the spectrum around an energy of order a few hundred GeV, first observed by the magnetic spectrometers PAMELA and AMS02, has now been confirmed by several calorimeter detectors (ATIC, CREAM, CALET, NUCLEON and DAMPE). These new measurements

High energy cosmic rays reach the surface of the Sun and start showers with thousands of secondary particles. Most of them will be absorbed by the Sun, but a fraction of the neutral ones will escape and reach the Earth. Here we incorporate a new ingredient that is essential to understand the flux of these solar particles: the cosmic ray shadow of the Sun. We use Liouville’s theorem to argue that the

We report five measurements of the transverse baryonic acoustic scale, θBAO, obtained from the angular two-point correlation function calculation for Luminous Red Galaxies of the eleventh data release of the Sloan Digital Sky Survey (SDSS). Each measurement has been obtained by considering a thin redshift shell (Δz=0.01 and 0.02) in the interval z ∈ [0.565, 0.660], which contains a large density of

On August 17, 2017, the first gravitational wave signal from a binary neutron star inspiral (GW170817) was detected by Advanced LIGO and Advanced VIRGO. Here we present radioactive β-decay rates of three independent sources 44Ti, 60Co and 137Cs, monitored during the same period by a precision experiment designed to investigate the decay of long-lived radioactive sources. We do not find any significant

The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a design concept for a next-generation UHECR observatory, addressing the requirements for a large-area, low-cost detector suitable for measuring the properties of ultra-high energy cosmic rays (UHECRs), having energies exceeding 30 EeV, with an unprecedented aperture. We have developed a full-scale prototype consisting of four 200 mm

Transient and variable phenomena in astrophysical sources are of particular importance to understand the underlying gamma-ray emission processes. In the very-high energy gamma-ray domain, transient and variable sources are related to charged particle acceleration processes that could for instance help understanding the origin of cosmic-rays. The imaging atmospheric Cherenkov technique used for gamma-ray

The High Energy Stereoscopic System (H.E.S.S.) is one of the three arrays of imaging atmospheric Cherenkov telescopes (IACTs) currently in operation. It is composed of four 12-meter telescopes and a 28-meter one, and is sensitive to gamma rays in the energy range ~ 30 GeV – 100 TeV. The cameras of the 12-m telescopes recently underwent a substantial upgrade, with the goal of improving their performance

In this paper I examine how well Ryskin’s model of emergent cosmic acceleration fits several sets of cosmological observations. I find that while Ryskin’s model is somewhat compatible with the standard model of cosmic acceleration (ΛCDM) for low redshift (z ≲ 1) measurements, its predictions diverge considerably from those of the standard model for measurements made at high redshift (for which z ≳ 1)

The IceCube Neutrino Observatory has revealed the existence of sources of high-energy astrophysical neutrinos. However, identification of the sources is challenging because astrophysical neutrinos are difficult to separate from the background of atmospheric neutrinos produced in cosmic-ray-induced particle cascades in the atmosphere. The efficient detection of air showers in coincidence with detected

The EAS Cherenkov light array Tunka-133, with ~ 3 km2 geometric area, is taking data since 2009.The array permits a detailed study of energy spectrum and mass composition of cosmic rays in the energy range from 6 · 1015 to 1018 eV. We describe the methods of time and amplitude calibration of the array and the methods of EAS parameters reconstruction. We present the all-particle energy spectrum, based

A known criticality of optical cavities such as Fabry–Pérot resonant cavities is the presence of non-linear effects in the build-up of the laser fields inside the cavity itself, which can spoil the characteristics of the error signal used to control the cavity length, usually obtained with the Pound–Drever–Hall phase modulation–demodulation technique. The non-linear effects are primarily caused by

We consider a warm inflation universe model in the presence of generalized Chaplygin gas and modified Chaplygin gas by taking Dirac-Born-Infeld non-canonical scalar field. For developing various inflationary parameters, we assume quadratic potential and quartic potential and Anti-de-Sitter warp factor for the Dirac-Born-Infeld inflation. We develop the number of e-folds, scalar as well as tensor power

The experiment on recording neutrino bursts operates since the mid-1980. As a target, we use two parts of the facility with a total mass of 240 tons. The current status of the experiment and some results related to the investigation of background events and the stability of facility operation are presented. Over the period of June 30, 1980 to December 31, 2018, the actual observational time is 33.02

With 8 h of observations, VERITAS confirms the detection of two very high energy gamma-ray sources. The gamma-ray binary LS 5039 is detected with a statistical significance of 8.8σ. The measured flux above 1 TeV is (2.5±0.4)×10−12cm−2s−1 near inferior conjunction and (7.8±2.8)×10−13cm−2s−1 near superior conjunction. The pulsar wind nebula HESS J1825-137 is detected with a statistical significance of

Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric

Radio galaxies host relativistic jets oriented away from our line of sight, making them challenging targets for Very High Energy (VHE, E > 100 GeV) γ-ray detectors. Indeed, out of ∼ 100 extragalactic sources detected at E > 100 GeV, only six are radio galaxies, while the great majority are blazars hosting aligned jets. The new Cherenkov Telescope Array (CTA) will provide order-of-magnitude improvements

Deep underground environments are ideal for low background searches due to the attenuation of cosmic rays by passage through the earth. However, they are affected by backgrounds from γ-rays emitted by 40K and the 238U and 232Th decay chains in the surrounding rock. The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a liquid xenon TPC located within the Davis campus

COSINE-100 is a direct detection dark matter search experiment that uses a 106 kg array of eight NaI(Tl) crystals that are kept underground at the Yangyang Underground Laboratory to avoid cosmogenic activation of radioisotopes by cosmic rays. Even though the cosmogenic activity is declining with time, there are still significant background rates from the remnant nuclides. In this paper, we report measurements