Speaker
yoann genolini
(LAPTh)
Description
The positron fraction in cosmic rays has recently been measured with improved accuracy up to 500 GeV, and
it was found to be a steadily increasing function of energy above $\sim$ 10 GeV. This behaviour contrasts with standard
astrophysical mechanisms, in which positrons are secondary particles, produced in the interactions of primary cosmic rays during
their propagation in the interstellar medium. The observed anomaly in the positron fraction triggered a lot of excitement, as
it could be interpreted as an indirect signature of the presence of dark matter species in the Galaxy, the so-called weakly interacting massive particles (WIMPs). Alternatively, it could be produced by nearby sources, such as pulsars.
These hypotheses are probed in light of the latest AMS-02 positron fraction measurements. The cosmic ray positron transport in the Galaxy is described using a semi-analytic two-zone model. For consistency, the
secondary and primary components of the positron flux are calculated together with the same propagation
model. We show that the results inferred for both hypotheses crucially depend on the propagation parameters, estimated with the Boron-to-Carbon ratio. Their uncertainties turn out to be very significant, and overshadow even the statical errors from the positron
data.
| Registration number following "ICRC2015-I/" | 839 |
|---|---|
| Collaboration | -- not specified -- |
Primary authors
Antje Putze
(Centre National de la Recherche Scientifique (FR))
Genevieve Belanger
(LAPP Annecy)
Mathieu Boudaud
(LAPTh Annecy France)
Sami Caroff
(Centre National de la Recherche Scientifique (FR))
Sandy Aupetit
(Centre National de la Recherche Scientifique (FR))
yoann genolini
(LAPTh)
Co-authors
Corinne Goy
(Centre National de la Recherche Scientifique (FR))
Li Tao
(Centre National de la Recherche Scientifique (FR))
Manuela Vecchi
(Universidade de Sao Paulo (BR))
PIERRE SALATI
(LAPTh & Université de Savoie Mont Blanc)
Sylvie Rosier
(Centre National de la Recherche Scientifique (FR))
Vincent Poireau
(Centre National de la Recherche Scientifique (FR))
Mr
Vivian Poulin
(LAPTh)
