Transition radiation in high energy showers

Abstract

Radio detection of particle showers is one of the most promising techniques for the detection of ultra high energy cosmic rays and neutrinos. Low fluxes at high energies and low neutrino cross-sections demand immense exposures to detect them. The radio detection technique allows this thanks to a duty cycle of 24 hours and radio waves having attenuation lengths of the order of kilometers in naturally abundant media such as the atmosphere or glacial ice. This, together with the low cost per station, allows to instrument enormous effective volumes to collect data for long periods of time. Technological advancements in computing and signal processing have paved the way for an outstanding improvement of the theoretical modeling of the radio pulses and their experimental study, greatly boosting the potential of the technique. The main topic of this thesis is coherent transition radiation as a shower transits form one medium to another, partly motivated by a plausible explanation of the so-called anomalous ANITA events that have attracted a lot of attention because they are not easy to explain.