Wuppertal 2015 – scientific programme

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T: Fachverband Teilchenphysik

T 92: Kosmische Strahlung VII

T 92.1: Talk

Thursday, March 12, 2015, 16:45–17:00, I.13.65 (HS 26)

Search for Positron Anisotropies with the Alpha Magnetic Spectrometer — •Fabian Machate — 1. Physikalisches Institut B, RWTH Aachen University, Germany

Several experiments have seen a significant excess of cosmic ray positrons over the background at energies above 10 GeV. Since such an excess is not expected for secondary cosmic rays, several models have been discussed as a possible explanation. Nearby pulsars or annihilating dark matter particles as a primary source of electrons and positrons are the most popular ones. A possible way of distinguishing between pulsar and dark matter origin is the measurement of dipole anisotropies in the positron flux or the positron to electron ratio. Such anisotropies are reduced by diffusion in galactic magnetic fields.

The Alpha Magnetic Spectrometer (AMS-02) on the International Space Station is the leading space-based experiment for cosmic ray detection and well suited for this search. The analysis procedure for anisotropy detection will be presented and mechanisms to improve the upper limits on the dipole anisotropy will be discussed.