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arXiv · 1712.05089

DAMPE squib? Significance of the 1.4 TeV DAMPE excess

Andrew Fowlie
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Abstract

We present a Bayesian and frequentist analysis of the DAMPE charged cosmic ray spectrum. The spectrum, by eye, contained a spectral break at about 1 TeV and a monochromatic excess at about 1.4 TeV. The break was supported by a Bayes factor of about $10^{10}$ and we argue that the statistical significance was resounding. We investigated whether we should attribute the excess to dark matter annihilation into electrons in a nearby subhalo. We found a local significance of about $3.6\sigma$ and a global significance of about $2.3\sigma$, including a two-dimensional look-elsewhere effect by simulating 1000 pseudo-experiments. The Bayes factor was sensitive to our choices of priors, but favoured the excess by about 2 for our choices. Thus, whilst intriguing, the evidence for a signal is not currently compelling.

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Andrew Fowlie. 2017-12-14. DAMPE squib? Significance of the 1.4 TeV DAMPE excess. https://doi.org/10.1016/j.physletb.2018.03.006

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