content_image/355815.jpg
<img src='content_image/355815.jpg'>

τ$_{D}$ . Compared with the PAMELA data, the Fermi-LAT data is more sensitive to m$_{D}$ , which is due to more data points at high energy region and higher statistics. If simultaneously adjusting both m$_{D}$ and τ$_{D}$ , in all the cases from SH-I to SH-IV, one can obtain the nearly the same positron fraction ( E ≲ 100 GeV) to explain the PAMELA data as shown in Fig. 

