Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 46: Cosmic Rays II

T 46.5: Talk

Tuesday, March 16, 2021, 17:00–17:15, Tu

Analysis of photon-like air showers measured by the Pierre Auger Observatory — •Jannis Pawlowsky for the Pierre Auger collaboration — Bergische Universität Wuppertal, Gaußstr. 20, 42119 Wuppertal

The Pierre Auger Observatory is the largest experiment measuring ultra high energy cosmic rays. It has sensitivity to the primary particle type from the differences in the way showers develop. This leads to the Pierre Auger Observatory presently being the most sensitive detector for photons and neutrinos at energies above the EeV range. For the search of photons, the 12 years of the Surface Detector data was used. The detectors are able to discriminate the electromagnetic and hadronic shower component by the shape of the measured time traces and by the lateral particle density distribution of the air shower. These observables are combined in a principal component analysis (PCA) resulting in a photon-like parameter. In this, the distributions for hadrons and photons are well separated. Photon candidates have been selected by applying a PCA threshold corresponding to a 50% photon detection efficiency. Applied to the full dataset, 13 candidates in the tail of the data-distribution were found.
To test a hadron hypothesis, events with highly energetic π⁰ secondaries have been simulated and analysed. Results for the characterization of these photon-like hadronic showers and the probability to be misinterpreted as photon candidates are presented.
*Supported by the BMBF Verbundforschung Astroteilchenphysik (Vorhaben 05A17PX1/05A20PX1).