Bayesian analysis of the mass composition of Ultra-High Energy Cosmic Rays using Xmax data recorded at the Pierre Auger Observatory
- Autores: Guillermo Torralba Elipe
- Directores de la Tesis: Enrique Zas Arregui (dir. tes.)
- Lectura: En la Universidade de Santiago de Compostela ( España ) en 2017
- Idioma: inglés
- Tribunal Calificador de la Tesis: Andrew Watson (presid.), Ricardo Vázquez López (secret.), Lorenzo Cazón Boado (voc.)
- Programa de doctorado: Programa de Doctorado en Física Nuclear y de Partículas por la Universidad de Santiago de Compostela
- Materias:
- Enlaces
- Tesis en acceso abierto en: MINERVA
- Resumen
Understanding the composition of Ultra High Energy Cosmic Rays (UHECRs) at Earth is crucial to unveil their origin and propagation mechanisms, and it is thus one of the main current challenges in the field of Astroparticle Physics. This thesis is aimed to study the mass composition of UHECRs using data measured at the Pierre Auger Observatory in a Bayesian approach. An innovative method for composition analysis based on Bayesian statistics is developed. This is then applied to Auger data to infer the composition of UHECRs under different primary cosmic ray mass scenarios and assuming different hadronic interaction models. As a result a transition from intermediate to lighter masses from 0.63 EeV to 2 EeV is found. Above this energy the composition becomes heavier as energy increases. Using these results and the all particle spectrum measured at the Auger Observatory a first estimate of the proton flux is inferred and its astrophysical interpretations are discussed.
