arXiv subjects

Mario Bertaina

Publications and source records attributed to Mario Bertaina.

23 records · Page 2Linked to original sources

arXiv2019

A More Complete Phenomenology of Tau Lepton Induced Air Showers

Many proposed and upcoming experiments seek to observe signals from upward going air showers initiated by tau leptons resulting from neutrino interactions inside the Earth. To save calculation time, event estimations for these observation methods are usually performed while making several assumptions about the showers themselves, which simplifies their rich phenomenology and may or may not lead to inaccuracies in results. Here, we present results of extensive CORSIKA simulations of upward going tau initiated showers in the energy range 1 PeV to 10 EeV. Specifically, we monitor the Cherenkov emission, the charged particle distributions, and the timing of the showers for different geometric configurations. We analyze the impact of the decay length and different decay modes of the tau on particle distributions and compare to primaries usually utilized to simulate a tau shower, such as gammas, electrons, and protons. We also check the accuracy of many of the usual assumptions of these showers and analyze the often ignored muon channel of the tau decay.

hep-ph↗

arXiv2019

Weather Research and Forecasting) model and radiative methods for cloud top height retrieval along the EUSO-SPB1 trajectory

The Extreme Universe Space Observatory-Super Pressure Balloon (EUSO-SPB1) is a pathfinder of the JEM-EUSO program, which aims to observe Ultra High Energy Cosmic Rays (UHECRs) from near-space. It was launched from Wanaka (New Zealand) on April 25, 2017 UTC and was terminated after twelve days of flight in the South Pacific Ocean. A good knowledge of the atmospheric conditions and cloud properties, such as the Cloud Top Height (CTH), is fundamental to correctly reconstruct the energy and geometry of air showers produced by cosmic rays passing through the atmosphere. One of the methods used to retrieve the CTH is based on Numerical Weather Prediction models. In this work, we consider in particular the Weather Research and Forecasting (WRF) model. A first model test is made on the WRF parametrizations for elementary processes, applying a top-bottom directed algorithm based on two quantities: cloud fraction and optical depth. The validated procedure is then applied to the SPB1 trajectory, retrieving the CTH every ten minutes for the days of the flight. A comparison is made with the analyzed data taken from MODerate resolution Imaging Spectroradiometer (MODIS) satellite images, once per day, to understand the reliability of the method. Another way to retrieve the CTH is the so-called radiative method, that allows to calculate the Cloud Top Temperature (CTT). A vertical temperature profile is needed to transform the CTT into CTH. When radiosoundings are not available, WRF can provide vertical temperature profiles. The conversion from the CTT to the CTH is then made.

physics.ao-ph↗

arXiv2019

Search for Ultra High Energy Cosmic Rays from Space -- The JEM-EUSO Program

The origin and nature of Ultra-High Energy Cosmic Rays (UHECRs) remain unsolved in contemporary astroparticle physics. To give an answer to these questions is rather challenging because of the extremely low flux of a few per km$^2$ per century at extreme energies (i.e. E $>$ 5$\times$10$^{19}$ eV). The central objective of the JEM-EUSO program, Joint Experiment Missions for Extreme Universe Space Observatory, is the realisation of an ambitious space-based mission devoted to UHECR science. A super-wide-field telescope will look down from space onto the night sky to detect UV photons emitted from air showers generated by UHECRs in the atmosphere. The JEM-EUSO program includes several missions from ground (EUSO-TA), from stratospheric balloons (EUSO-Balloon, EUSO-SPB1, EUSO-SPB2), and from space (TUS, Mini-EUSO) employing fluorescence detectors to demonstrate the UHECR observation from space and prepare the large size missions K-EUSO and POEMMA. We review the scientifical objectives associated with the developing projects of the JEM-EUSO program and the technological achievements allowing them.

astro-ph.IM↗

arXiv2015

Detection of Earth-skimming UHE tau neutrino with the JEM-EUSO detector

The ultra high energy cosmic neutrinos are powerful astrophysical probes for both astrophysical mechanisms of particle acceleration and fundamental interactions. They open a window into the very distant and high-energy Universe that is difficult to access by any human means and devices. The possibility of detecting them in large exposure space-based apparatus, like JEM-EUSO, is an experimental challenge. In this paper we present an estimation of the feasibility of detection of UHE tau neutrino by the JEM-EUSO telescope. The interactions of tau-neutrino in sea water and Earth's crust have been investigated. The estimation of the propagation length and energy of the outgoing tau-lepton shows that if its decay occurs in the atmosphere close enough to the Earth's surface, e.g. below $\sim$ $5 km$ altitude, the cascade is intensive enough and the generated light can be detected from space. We have evaluated the geometrical aperture of the JEM-EUSO detector for the Earth-skimming (horizontal and upward-going) tau-neutrinos by making specific modifications to the standard CORSIKA code and developing an interface to the existing ESAF (EUSO Simulation and Analysis Framework) software.

astro-ph.IM↗

arXiv2015

Sensitivity of the JEM-EUSO telescope to gravity effects in neutrino-induced air showers

We examine the JEM-EUSO sensitivity to gravity effects in the context of Randall-Sundrum (RS) model with a single extra dimension and small curvature of the metric. Exchanges of reggeized Kaluza-Klein gravitons in the $t$-channel contribute to the inelastic cross-section for scattering of ultra-high-energy neutrinos off nucleons. Such effects can be detected in deeply penetrating quasi-horizontal air showers induced by interactions of cosmic neutrinos with atmospheric nucleons. For this reason, we calculate the expected number of quasi-horizontal air showers at the JEM-EUSO observatory as a function of two parameters of the RS model.

astro-ph.HE↗