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τ$_{D}$ = 0 . 4 × 10 26 s. The case SH(LH) -IV is a kind of mixture with equal Yukawa couplings for all generation leptons, and the required mass and lifetime are found close to the case SH(LH)-I. As indicated in Fig. 3, the SH-I case can explain both the PAMELA and ATIC data. In this case, the DM particle decays directly into 4 e , which usually leads to a too hard spectrum to meet the Fermi-LAT data. The SH-II ∼ IV cases involving µ - and τ -lepton as final states can reproduce the PAMELA and Fermi-LAT results well with the parameters in Tab. III. The differences among the four cases are not obvious in the low energy rang E ≲ 100 GeV. However, in higher energy range E ≳ 1 TeV, the heavier final state case leads to harder energy spectrum. The SH-III case with 4 τ final states has the hardest spectrum among all the cases in this energy region. 

