A Brief Review on Dark Matter Annihilation Explanation for e± Excesses in Cosmic Ray
نویسنده
چکیده
Recently data from PAMELA, ATIC, FERMI-LAT and HESS show that there are e excesses in the cosmic ray energy spectrum. PAMELA observed excesses only in e, but not in anti-proton spectrum. ATIC, FERMI-LAT and HESS observed excesses in e + e spectrum, but the detailed shapes are different which requires future experimental observations to pin down the correct data set. Nevertheless a lot of efforts have been made to explain the observed e excesses, and also why PAMELA only observed excesses in e but not in antiproton. In this brief review we discuss one of the most popular mechanisms to explain the data, the dark matter annihilation. It has long been known that about 23% of our universe is made of relic dark matter. If the relic dark matter was thermally produced, the annihilation rate is constrained resulting in the need of a large boost factor to explain the data. We will discuss in detail how a large boost factor can be obtained by the Sommerfeld and BrietWigner enhancement mechanisms. Some implications for particle physics model buildings will also be discussed.
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