According to Einstein's theory of special relativity energy can be transformed into mass and vice versa. A dramatic demonstration of this principle is the release of the energy inherent in a few kilograms of Plutonium as radiation and ultimately heat (accelerated matter) in the explosion of a nuclear bomb. An example of the opposite process, the conversion of energy into matter occurs every time ultra-high energy radiation (so-called ultra-high energy cosmic rays) enters the Earth's atmosphere and interacts with the atoms therein. In this interaction a fraction of the energy is converted into new matter (particles) and radiation which then in turn can interact with the atoms in the atmosphere and so on. Such cascades of particles and radiation are called extensive air showers. They are observed regularly with scientific installations such as the Pierre Auger Observatory, either by observing the radiation that is emitted as the cascade develops in the atmosphere with special UV telescopes or by detecting the matter that reaches the ground with an array of particle detectors. Cosmic rays have been observed since the early 1900s and the ultra-high energy cosmic rays are being studied since the 1980s. Nevertheless their origin remains unknown to this day. In addition it has been observed for a while now that the matter content observed in such air showers does not match our expectations. Specifically the measurements with particle detectors at the ground suggest that matter in the form of muons (an elementary particle) occurs much more frequent than what we expect (referred to as the muon puzzle).
The aim of this project is to shed new light on the muon puzzle by providing a new precision measurement of the muon content in air showers by using the novel technique of measuring the radiation emitted in the atmosphere with radio antennas instead of UV telescopes. These radio observations have been carried out between 2016 and 2019 but the data were not used sofar because the analysis of the particle detectors for the corresponding data has been missing. The main objectives of this project are to: 1) implement an analysis of the particle detector measurements (so-called reconstruction). 2) combine these with the radio data including data cleaning (for example removing periods with thunderstorms where there is a lot of radio background in the atmosphere), 3) analyze the combined data for the muon content.
