A search for ultra-high energy neutrinos and cosmic-rays with ANITA-2

• Main Author: Mottram, M.J.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UCL (University College London) 2012
• Subjects: Antarctic; The Antarctic; Antarc*; Ice Sheet
• Online Access: https://discovery.ucl.ac.uk/id/eprint/1344072/1/1344072.pdf; https://discovery.ucl.ac.uk/id/eprint/1344072/

The ANtarctic Impulsive Transient Antenna (ANITA) experiment is a balloon-borne array of radio antennas designed to search for ultra-high energy neutrinos by observing the Antarctic ice sheet for radio emission that is expected to arise as a result of the neutrinos’ interaction. ANITA is further able to detect radio emission that arises when ultra-high energy cosmic-rays interact in the Earth’s atmosphere. The second flight of the experiment, ANITA-2, took place in 2008-09 over 31 days. This thesis describes an analysis of the ANITA-2 dataset and presents results from searches for ultra-high energy neutrinos and cosmic-rays. No statistical evidence of emission from neutrino interactions is observed, with two candidate events discovered on a background of 1:13 \pm 0:27. A limit on the diffuse flux of ultra-high energy neutrinos is presented, further model-independent and model-dependent flux limits on selected active galactic nuclei are calculated. Four isolated and one non-isolated cosmic-ray candidates are discovered. The identity of the isolated candidates as cosmic-ray-induced radio emission is confirmed through correlation between observed and expected emission polarisation.