Explanations of the DAMPE high energy electron/positron spectrum in the dark matter annihilation and pulsar scenarios

Abstract

Many studies have shown that either the nearby astrophysical source or dark matter (DM) annihilation/decay can be used to explain the excess of high energy cosmic ray (CR) e±, which is detected by many experiments, such as PAMELA and AMS-02. Recently, the dark matter particle explorer (DAMPE) collaboration has reported its first result of the total CR e± spectrum from 25 GeV to 4.6 TeV with high precision. In this work, we study the DM annihilation and pulsar interpretations of this result. We show that the leptonic DM annihilation channels to τ+τ−, 4μ, 4τ, and mixed charged lepton final states can well explain the DAMPE e± spectrum. We also find that the mixed charged leptons channel would lead to a sharp drop structure at ~ TeV. However, the ordinary DM explanations have been almost excluded by the constraints from the observations of gamma-ray and CMB, unless some exotic DM models are introduced. In the pulsar scenario, we analyze 21 nearby known pulsars and assume that one of them dominantly contributes to the high energy CR e± spectrum. Involving the constraint from the Fermi-LAT observation of the e± anisotropy, we find that two pulsars could explain the DAMPE e± spectrum. Our results show that it is difficult to discriminate between the DM annihilation and single pulsar explanations of high energy e± with the current DAMPE result.