arXiv subjects

D. Veberič

Publications and source records attributed to D. Veberič.

8 recordsLinked to original sources

arXiv2025

Investigating double bump air showers with the SKA-Low

Double-bump showers are a rare class of extensive air showers (EAS) predicted by Monte Carlo simulations. They occur when a high-energy secondary particle, the leading particle, travels significantly farther than the rest, creating a distinct double-peaked longitudinal profile. So far, no experiment has been able to directly detect these showers. The unique radio footprint of double-bump showers, characterized by multiple Cherenkov rings, provides a way to reconstruct longitudinal profiles from radio observations. With its dense antenna array and broad frequency range, the Square Kilometer Array Observatory (SKAO) will be the first experiment capable of detecting these features, offering a new opportunity to probe hadronic interactions and constrain particle cross sections at high energies. In our analysis, we simulate the EAS using CORSIKA with the CoREAS plugin for radio. We developed a new method based on the Akaike information criterion to identify double bump showers in simulations by analyzing their longitudinal profiles. Then we investigate the prevalence of these double bump showers across different cosmic ray primary particles and various hadronic interaction models. We create a skeleton of the EAS which consists of all the particles with at least $1\%$ of the primary energy, allowing us to confirm the leading particle hypothesis and track shower development following these particles. This will enable us to relate the attributes of the leading particle to measurable parameters. Depending on the exact shower properties, the radio footprint of a double bump shower can create a complex interference pattern, consisting of multiple rings. From this information, the longitudinal profiles can be extracted. SKA due to its dense antenna array and frequency range will be the first experiment able to observe these double bump showers in detail.

astro-ph.HE↗

arXiv2025

A novel approach for air shower profile reconstruction with dense radio antenna arrays using Information Field Theory

Reconstructing the longitudinal profile of extensive air showers, generated from the interaction of cosmic rays in the Earth's atmosphere, is crucial to understanding their mass composition, which in turn provides valuable insight on their possible sources of origin. Dense radio antenna arrays such as the LOw Frequency ARray (LOFAR) telescope as well as the upcoming Square Kilometre Array Observatory (SKAO) are ideal instruments to explore the potential of air shower profile reconstruction, as their high antenna density allows cosmic ray observations with unprecedented accuracy. However, current analysis approaches can only recover $X_\mathrm{max}$, the atmospheric depth at shower maximum, and heavily rely on computationally expensive simulations. As such, it is ever more crucial to develop new analysis approaches that can perform a full air shower profile reconstruction efficiently. In this work, we develop a novel framework to reconstruct the longitudinal profile of air showers using measurements from radio detectors with Information Field Theory (IFT), a state-of-the-art reconstruction framework based on Bayesian inference. Through IFT, we are able to exploit all available information in the signal (amplitude, phase, and pulse shape) at each antenna position simultaneously and explicitly utilise models that are motivated through our current understanding of air shower physics. We verify our framework on simulated datasets prepared for LOFAR, showcasing that we can not only reconstruct the air shower profile with uncertainties in each atmospheric depth bin but also recover the reconstructed trace at each antenna position. Our framework demonstrates that radio measurements with dense antenna layouts such as LOFAR and SKAO have the capability to go beyond reconstruction of $X_\mathrm{max}$ and will thus aid in our understanding of the mass composition of cosmic rays.

astro-ph.IM↗

arXiv2023

Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers

The present white paper is submitted as part of the "Snowmass" process to help inform the long-term plans of the United States Department of Energy and the National Science Foundation for high-energy physics. It summarizes the science questions driving the Ultra-High-Energy Cosmic-Ray (UHECR) community and provides recommendations on the strategy to answer them in the next two decades.

astro-ph.HE↗

arXiv2020

Limits from the Funk Experiment on the Mixing Strength of Hidden-Photon Dark Matter in the Visible and Near-Ultraviolet Wavelength Range

We present results from the FUNK experiment in the search for hidden-photon dark matter. Near the surface of a mirror, hidden photons may be converted into ordinary photons. These photons are emitted perpendicular to the surface and have an energy equal to the mass of the dark matter hidden photon. Our experimental setup consists of a large, spherical mirror with an area of more than 14 m$^2$, which concentrates the emitted photons into its central point. Using a detector sensitive to visible and near-UV photons, we can exclude a kinetic-mixing coupling of stronger than $χ\approx 10^{-12}$ in the mass range of 2.5 to 7 eV, assuming hidden photons comprise all of the dark matter. The experimental setup and analysis used to obtain this limit are discussed in detail.

astro-ph.CO↗

arXiv2017

Search for hidden-photon dark matter with the FUNK experiment

Many extensions of the Standard Model of particle physics predict a parallel sector of a new U(1) symmetry, giving rise to hidden photons. These hidden photons are candidate particles for cold dark matter. They are expected to kinetically mix with regular photons, which leads to a tiny oscillating electric-field component accompanying dark matter particles. A conducting surface can convert such dark matter particles into photons which are emitted almost perpendicularly to the surface. The corresponding photon frequency follows from the mass of the hidden photons. In this contribution we present a preliminary result on a hidden photon search in the visible and near-UV wavelength range that was done with a large, 14 m2 spherical metallic mirror and discuss future dark matter searches in the eV and sub-eV range by application of different detectors for electromagnetic radiation.

hep-ex↗

arXiv2017

Search for hidden-photon Dark Matter with FUNK

It has been proposed that an additional U(1) sector of hidden photons could account for the Dark Matter observed in the Universe. When passing through an interface of materials with different dielectric properties, hidden photons can give rise to photons whose wavelengths are related to the mass of the hidden photons. In this contribution we report on measurements covering the visible and near-UV spectrum that were done with a large, 14 m2 spherical metallic mirror and discuss future dark-matter searches in the eV and sub-eV range by application of different electromagnetic radiation detectors.

hep-ex↗

arXiv2015

A likelihood method to cross-calibrate air-shower detectors

We present a detailed statistical treatment of the energy calibration of hybrid air-shower detectors, which combine a surface detector array and a fluorescence detector, to obtain an unbiased estimate of the calibration curve. The special features of calibration data from air showers prevent unbiased results, if a standard least-squares fit is applied to the problem. We develop a general maximum-likelihood approach, based on the detailed statistical model, to solve the problem. Our approach was developed for the Pierre Auger Observatory, but the applied principles are general and can be transferred to other air-shower experiments, even to the cross-calibration of other observables. Since our general likelihood function is expensive to compute, we derive two approximations with significantly smaller computational cost. In the recent years both have been used to calibrate data of the Pierre Auger Observatory. We demonstrate that these approximations introduce negligible bias when they are applied to simulated toy experiments, which mimic realistic experimental conditions.

astro-ph.IM↗

arXiv2009

Studies of the UHECR propagation in the Galactic Magnetic Field

We present the results of simulations of the ultra-high energy cosmic ray (UHECR) propagation in the Galactic magnetic field (GMF). Different assumptions on the large-scale GMF structure and/or primary particle lead to distinctly different deflection patterns of the highest energy cosmic rays (CR). The GMF modifies the exposure of an UHECR experiment to the extragalactic sky. We estimated these effects for the Pierre Auger experiment. Further forward-tracking studies under plausible UHECR sources scenarios will allow for direct comparison with the observed correlation between the nearby active galactic nuclei (AGN) and the highest energy Auger events.

astro-ph.HE↗