Download Free Composition Studies Of Ultra High Energy Cosmic Rays Using Data Of The Pierre Auger Observatory Book in PDF and EPUB Free Download. You can read online Composition Studies Of Ultra High Energy Cosmic Rays Using Data Of The Pierre Auger Observatory and write the review.

The Pierre Auger Observatory (Auger) in Argentina studies Ultra High Energy Cosmic Rays (UHECRs) physics. The flux of cosmic rays at these energies (above 1018 eV) is very low (less than 100 particle/km2-year) and UHECR properties must be inferred from the measurements of the secondary particles that the cosmic ray primary produces in the atmosphere. These particles cascades are called Extensive Air Showers (EAS) and can be studied at ground by deploying detectors covering large areas. The EAS physics is complex, and the properties of secondary particles depend strongly on the first interaction, which takes place at an energy beyond the ones reached at accelerators. As a consequence, the analysis of UHECRs is subject to large uncertainties and hence many of their properties, in particular their composition, are still unclear. Two complementary techniques are used at Auger to detect EAS initiated by UHE- CRs: a 3000 km2 surface detector (SD) array of water Cherenkov tanks which samples particles at ground level and fluorescence detectors (FD) which collect the ultraviolet light emitted by the de-excitation of nitrogen nuclei in the atmosphere, and can operate only in clear, moonless nights. Auger is the largest cosmic rays detector ever built and it provides high-quality data together with unprecedented statistics. The main goal of this thesis is the measurement of UHECR mass composition using data from the SD of the Pierre Auger Observatory. Measuring the cosmic ray composition at the highest energies is of fundamental importance from the astrophysical point of view, since it could discriminate between different scenarios of origin and propagation of cosmic rays. Moreover, mass composition studies are of utmost importance for particle physics. As a matter of fact, knowing the composition helps in exploring the hadronic interactions at ultra-high energies, inaccessible to present accelerator experiments.
The Pierre Auger Observatory studies Ultra High Energy Cosmic Rays (UHECRs) physics. The flux of UHECRs is very low (less than 1 particle/km2-year) and their properties must be inferred from the measurements of the secondary particles that the cosmic ray primary produces in the atmosphere. These particles cascades are called Extensive Air Showers (EAS) and can be studied at ground by deploying detectors covering large areas. The EAS physics is complex, and the properties of secondary particles depend strongly on the first interaction, which takes place at an energy beyond the ones reached at accelerators. As a consequence, the analysis of UHECRs is subject to large uncertainties and hence many of their properties, in particular their composition, are still unclear. Two complementary techniques are used at Auger to detect EAS initiated by UHECRs: a 3000 km2 surface detector (SD) array of water Cherenkov tanks which samples particles at ground level and fluorescence detectors (FD) which collect the ultraviolet light emitted by the de-excitation of nitrogen nuclei in the atmosphere, and can operate only in clear, moonless nights. The main goal of this thesis is the measurement of UHECR mass composition using data from the SD of the Pierre Auger Observatory. Measuring the cosmic ray composition at the highe-st energies is of fundamental importance for particle physics and astrophysics. Indeed, it allows to explore the hadronic interactions at ultra-high energies, and to discriminate between different scenarios of origin and propagation of cosmic rays.
The mass composition of cosmic rays is an important parameter for determining their origin. Using both fluorescence and surface detectors, The Pierre Auger Observatory measures the depth of shower maximum, Xmax, from which the mass of the primary particle can be inferred. The surface detector measurement, which is based on the principle of shower universality, increases the number of available statistics for Xmax by at least a factor of 10 since it is no longer limited by the low duty cycle of the fluorescence detector. We compare the energy and arrival directions determined using this new reconstruction to both the official surface and fluorescence detector reconstructions and present an event by event comparison of the \Xmax values calculated using both types of detectors for events with energies above 10^{18.8} eV. We use this new reconstruction method based on universality to conduct preliminary anisotropy studies discriminating by the mass of the primary particle.
Ultra-high energy cosmic rays are particles of enormous energy -- greater than 1018 eV -- reaching Earth from still mysterious sources. In this thesis, we analyze data from the Pierre Auger Observatory, a giant cosmic ray detector located in Argentina, to derive information on the mass of ultra-high energy cosmic rays and on their hadronic interaction properties. The data show a change of cosmic ray mass composition as a function of energy. We perform a measurement of the proton-air inelastic cross section, yielding sinelp-air =501+24-23 stat+30 -35syst +30-32 composition mb, at an equivalent energy of 57 TeV in the center of mass of a proton-proton collision -- a range yet inaccessible to particle accelerators. The measured cross section is in good agreement with predictions from hadronic interaction models.
The origin and composition of ultrahigh energy cosmic rays has been and continues to be a topic of much study and debate. The Pierre Auger Observatory was designed to investigate the highest energy cosmic rays and resolve some of these problems. In this dissertation, I present a description of the Pierre Auger Observatory and a study of the performance of the surface array as well as work done on the photomultiplier tubes used in the surface array. I also present an analysis done on the composition of the events detected in the surface detector paying special attention to a photon primary assumption. Monte carlo simulations of extensive air showers are put through a simulation of the surface detector and observables are compared to real data. The mean behavior of the real data is compared to various baryonic primary assumptions. For photon primaries, a method is described to set an upper limit on the flux of photons based on comparing real events to expected distributions for photon initiated air showers. An upper limit on the photon flux is presented and compared with predictions from various exotic models of cosmic ray origins.
Cosmic ray physics has recently attracted a great deal of attention from the high energy physics community because of the discovery of new sources and the advent of new techniques. The result of a series of lectures prepared for graduate students and postdoctoral researchers, this book is a general introduction to experimental techniques and results in the field of ultrahigh energy cosmic rays. It succinctly summarizes the rapidly developing field, and provides modern results that include data from newer detectors. Combining experiment and theory, the text explores the results of a single, easy-to-understand experiment to tie together various issues involved in the physics of ultrahigh energy cosmic rays.
Identifying the sources of the ultra-high energy cosmic rays (UHECRs, above 10^{18} eV), the most energetic particles known in the universe, would be an important leap forward for both the astrophysics and particle physics knowledge. However, developing a cosmic-ray astronomy is arduous because magnetic fields, that permeate our Galaxy and the extra-Galactic space, deflect cosmic rays that may lose the directional information on their sources. This problem can be reduced by studying the highest energy end of the cosmic ray spectrum. Indeed, magnetic field deflections are inversely proportional to the cosmic ray energy. Moreover, above 4x10^{19} eV, cosmic rays interact with cosmic photon backgrounds, losing energy. This means that the sources of the highest energy cosmic rays observed on Earth can be located only in the nearby universe (200 Mpc or less). The largest detector ever built for detecting cosmic rays at such high energies is the Pierre Auger Observatory, in Argentina. It combines a 3000 km^2 surface array of water Cherenkov detectors with fluorescence telescopes to measure extensive air showers initiated by the UHECRs. This thesis was developed inside the Auger Collaboration and was devoted to study the highest energy events observed by Auger, starting from the selection and reconstruction up to the analysis of their distribution in the sky. Moreover, since the composition at these energies is unknown, we developed a method to select proton-like events, since high Z cosmic rays are too much deflected by magnetic fields to be used for cosmic-ray astronomy.