Wuppertal 2015 – scientific programme
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T: Fachverband Teilchenphysik
T 73: Kosmische Strahlung IV
T 73.1: Talk
Wednesday, March 11, 2015, 16:45–17:00, I.12.01 (HS 30)
Identifying electrons and positrons with AMS-02 — •Nikolas Zimmermann — RWTH Aachen University
The AMS-02 experiment is a multi-purpose detector for cosmic ray particles mounted on the International Space Station. It recorded over 40 billion events since its installation in 2011.
The bulk of these events are protons, which are most abundant in cosmic rays. Electrons are 100 times and positrons 1000 times less abundant. Measuring the positrons as function of energy is especially interesting, as an excess over the expected astrophysical background may hint at an additional source of positrons in the galaxy or a new phenomena responsible for the excess, e.g. dark-matter annihilation.
In order to measure positrons accurately with a small uncertainty, a large proton rejection of 106 is needed. AMS-02 offers a transition radiation detector to separate positrons from protons and an electromagnetic calorimeter allowing a precise measurement of the kinetic energy of an incoming lepton. This talk will cover the general strategy of identifying electrons/positrons with AMS-02 and will present the so-obtained electron/positron fluxes that were recently published.