July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

Prospects for Measuring the Positron Excess with the Cherenkov Telescope Array

Jul 30, 2015, 3:00 PM
Mississippi (World Forum)


World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Oral contribution GA-EX Parallel GA 04


Prof. Justin Vandenbroucke (University of Wisconsin - Madison)


The excess of positrons in cosmic rays above ∼10 GeV has been a puzzle since it was discovered. Possible interpretations of the excess include acceleration of positron secondaries in local supernova remnants or pulsars, or the annihilation or decay of dark matter particles. To distinguish between these interpretations, the measurement of the positron fraction must be extended to higher energies. One technique to perform this measurement is using the Earth-Moon spectrometer: observing the deflection of positron and electron moon shadows by the Earth’s magnetic field. The measurement has been attempted by previous imaging atmospheric Cherenkov telescopes without success. The Cherenkov Telescope Array (CTA) will have unprecedented sensitivity and background rejection that could make this measurement successful for the first time. In addition, the possibility of using silicon photomultipliers in some of the CTA telescopes could greatly increase the feasibility of making observations near the moon. Estimates of the capabilities of CTA to measure the positron fraction using simulated observations of the moon shadow will be presented.
Registration number following "ICRC2015-I/" 1113
Collaboration CTA

Primary author

Dr Peter Karn (University of Wisconsin - Madison)


Prof. Justin Vandenbroucke (University of Wisconsin - Madison) Dr Matthew Wood (SLAC National Accelerator Laboratory) Pierre Colin (MPI fuer Physik)

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