Thesis

Phenomenology of Extensive Air Showers at 100 TeV scale

• Call:

  IDPASC Portugal - PHD Programme 2014

• Academic Year:

  2014 /2015

• Domains:

  Theoretical Particle Physics | Astroparticle Physics

• Supervisor:

  Lorenzo Cazon

• Co-Supervisor:

  Bernardo Tomé

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  Extensive air showers develop in a complex way as a combination of electromagnetic cascades and hadronic multiparticle production. It is necessary to perform detailed numerical simulations of air showers to infer the properties of the primary cosmic rays that initiate them. But simulations are a challenge since the number of charged particles in a high energy shower can be enormous. The design of algorithms is also hampered by limited knowledge of interaction cross-sections and particle production at high energies. Thus, development of models to unveil the dominant mechanisms that govern the cascades phenomenology are necessary in order to access the details of the high energy interactions. The hadronic cascade consists of a bulk of low energy mesons, mainly pions, of energies reachable by man made accelerators and fewer high energetic particles, leading barions and other mesons that yet carry a large fraction of the total energy. The energy and momentum of these leading particles depend on the details of the high energy interaction models, and determine the lower energy production of the bulk of mesons though the inelasticity, partition function and multiplicity. The Pierre Auger Observatory consists on a surface detector array (SD), sampling the particles - namely muons, electrons and photons- arriving at ground in an area of 3000 km² in the Argentinean Pampa, and a fluorescence detector (FD) imaging the development of the electromagnetic component of the shower in the atmosphere. The hybrid nature is a crucial feature of the observatory, each sub-detector giving complementary information. The observatory is also to deploy a series of complementary detectors that include: antennas for radio detection, a second detector acompanying all Cerenkov tanks (yet to be decided the specifics, the so called B2015), a set of buried scintillators (AMIGA), and an engeneering of segmented RPCs beneath the Cerenkov tanks (MARTA engeneering array). The work program of this thesis consists on the study of the different mechanisms that play a role on the development of the shower and give rise to the observables that Auger can measure. The objective is to model the cascade and gain insight into the phenomenology of the shower development with the aim to extract constraints to high energy physics models and composition of the primary beam.