arXiv:1304.1840astro-ph.HE
Dark Matter and Pulsar Origins of the Rising Cosmic Ray Positron Fraction in Light of New Data From AMS
Early discovery. Linked by one identifiable commenter. This paper is outside the main ranking; a mention is not an endorsement.
Abstract
The rise of the cosmic ray positron fraction with energy, as first observed with high confidence by PAMELA, implies that a large flux of high energy positrons has been recently (or is being currently) injected into the local volume of the Milky Way. With the new and much more precise measurement of the positron fraction recently provided by AMS, we revisit the question of the origin of these high energy positrons. We find that while some dark matter models (annihilating directly to electrons or muons) no longer appear to be capable of accommodating these data, other models in which ~1-3 TeV dark matter particles annihilate to unstable intermediate states could still be responsible for the observed signal. Nearby pulsars also remain capable of explaining the observed positron fraction. Future measurements of the positron fraction by AMS (using a larger data set), combined with their anticipated measurements of various cosmic ray secondary-to-primary ratios, may enable us to further discriminate between these remaining scenarios.
Very strange to see this article posted now. This news from the AMS is over a year old. And clearly, there is considerable debate whether the positron excess is from dark matter particle annihilation or from nearby pulsars. There are many papers on the subject - here is just one…
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