Speaker
Prof.
Justin Vandenbroucke
(University of Wisconsin - Madison)
Description
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 |
Author
Dr
Peter Karn
(University of Wisconsin - Madison)
Co-authors
Prof.
Justin Vandenbroucke
(University of Wisconsin - Madison)
Dr
Matthew Wood
(SLAC National Accelerator Laboratory)
Pierre Colin
(MPI fuer Physik)
