Search the repository

A+ | A- | | SLO | ENG

Abstract: In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (�max) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with �max distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energydependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data.
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, extensive air shower, hadronic interactions, cross-section, Xmax
Published in RUNG: 23.01.2024; Views: 2083; Downloads: 6
Full text (917,40 KB)
This document has many files! More...

Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays (UHECR), extensive air showers, Auger Surface Detector (SD) array, depth of shower maximum
Published in RUNG: 21.12.2020; Views: 3051; Downloads: 69
Full text (850,78 KB)

Abstract: The Telescope Array is the largest experiment studying ultra-high energy cosmic rays in the northern hemisphere. The detection area of the experiment consists of an array of 507 surface detectors, and a fluorescence detector divided into three sites at the periphery. The viewing directions of the 38 fluorescence telescopes point over the air space above the surface array. In this paper, we describe a technique that we have developed for simulating the response of the array of surface detectors of the Telescope Array experiment. The two primary components of this method are (a) the generation of a detailed CORSIKA Monte Carlo simulation with all known characteristics of the data, and (b) the validation of the simulation by a direct comparison with the Telescope Array surface detector data. This technique allows us to make a very accurate calculation of the acceptance of the array. We also describe a study of systematic uncertainties in this acceptance calculation.
Keywords: cosmic ray, extensive air shower, simulation, surface detector
Published in RUNG: 19.05.2020; Views: 3287; Downloads: 0
This document has many files! More...

Abstract: Previous measurements of the composition of Ultra-High Energy Cosmic Rays (UHECRs) made by the High Resolution Fly’s Eye (HiRes) and Pierre Auger Observatory (PAO) are seemingly contradictory, but utilize different detection methods, as HiRes was a stereo detector and PAO is a hybrid detector. The five year Telescope Array (TA) Middle Drum hybrid composition measurement is similar in some, but not all, respects in methodology to PAO, and good agreement is evident between data and a light, largely protonic, composition when comparing the measurements to predictions obtained with the QGSJetII-03 and QGSJet-01c models. These models are also in agreement with previous HiRes stereo measurements, confirming the equivalence of the stereo and hybrid methods. The data is incompatible with a pure iron composition, for all models examined, over the available range of energies. The elongation rate and mean values of are in good agreement with Pierre Auger Observatory data. This analysis is presented using two methods: data cuts using simple geometrical variables and a new pattern recognition technique.
Keywords: Ultra-High Energy Cosmic Rays, Cosmic ray composition, Atmospheric fluorescence, Extensive air shower array, Hybrid, Telescope Array
Published in RUNG: 24.04.2020; Views: 3816; Downloads: 0
This document has many files! More...

Abstract: The Pierre Auger Observatory (Auger) in Mendoza, Argentina and the Telescope Array (TA) in Utah, USA aim at unraveling the origin and nature of Ultra-High Energy Cosmic Rays (UHECR). At present, there appear to be subtle differences between Auger and TA results and interpretations. Joint working groups have been established and have already reported preliminary findings. From an experimental standpoint, the Surface Detectors (SD) of both experiments make use of different detection processes not equally sensitive to the components of the extensive air showers making it to the ground. In particular, the muonic component of the shower measured at ground level can be traced back to the primary composition, which is critical for understanding the origin of UHECRs. In order to make direct comparisons between the SD detection techniques used by Auger and TA, a joint SD experimental research program is being developed. In the first phase, two Auger SD stations were deployed at the TA Central Laser Facility to compare station-level responses. This paper concentrates on the results obtained with the first Auger SD station (an “Auger North” design), which has been operating since October 2014. The second Auger SD station, identical to the ones being operated at Auger in Argentina (an “Auger South” design), was just deployed in June 2015. The second phase of this research program will be to co-locate six Auger North SD stations with TA stations in the field to compare event-level responses.
Keywords: Ultra-High Energy Cosmic Rays, Pierre Auger Observatory, Telescope Array, extensive air showers, secondary cosmic rays, muonic shower component, surface detectors
Published in RUNG: 08.03.2016; Views: 5562; Downloads: 191
Full text (1,42 MB)