Calculation and experimental analysis of the muon cross sections

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Muons are used as final messenger particles in astroparticle physics on the fields of neutrino astronomy and cosmic ray physics. Therefore, the interaction probability of muons is entering the interpretation of the astrophysical relevant data, i.e. the determination of neutrino energy spectra important to answer the question for the contributions of atmospheric, prompt and astrophysical neutrinos and their origin. Because of the high muon rate recorded with IceCube (high statistical precision), the this-exceeding systematic uncertainties from the existing calculations of the muon cross sections are contributing significantly to the total systematic uncertainty of the experiment.In this project, on the one hand the muon cross sections shall be calculated with means of theoretical physics to a higher precision. These new cross sections shall be implemented in the Monte Carlo algorithm PROPOSAL, developed by the applying group, to determine the experimental consequences of the remaining uncertainties. In this regard, it could already be shown, that the relevant contributions to the systematic uncertainty to be minimized are coming from the probability distribution of the muon energy losses rather than from the total interaction probability. In parallel, the independent data sets of the atmospheric and neutrino induced muons recorded with IceCube shall be used to test the quality of the cross section calculations, respectively to reconstruct the cross section as far as possible.The project is based on a multitude of preparatory studies of the applying group from the fields of computational science and statistics (data mining for the signal extraction, development of methods for the solution of inverse problems, development of efficient methods for the Monte Carlo simulation) and from the fields of experimental and theoretical physics (data analyses for the reconstruction of the lepton spectra in IceCube, development of methods for the QED calculation of the cross sections).The project aims after three years for a significant improvement of the differential and total muon cross sections, whose uncertainties shall be quantified with numerical and experimental means.