Left panel: leptons and channels with the additional assumption of universal branching fractions into lepton pairs. The positron fraction has been plotted for m_χ = 600 GeV (dashed-dotted lines) and 20 TeV (solid lines), corresponding to ⟨ σv ⟩ = 1.05 × 10^-23 cm³ s^-1 and 1.12 × 10^-21 cm³ s^-1, and compared to AMS-02 data (Accardo et al. 2014). The 600 GeV DM species does not provide a good fit. The corresponding reduced χ² is of the order of 2. On the contrary, the 20 TeV WIMP reproduces the observations with a value of 0.6 but induces a sharp increase of the positron fraction above 1 TeV. Right panel: four-lepton channel. The positron fraction has been plotted for m_χ = 600 GeV (solid lines) and 20 TeV (dashed-dotted lines). The 600 GeV case provides a good fit with a value of 0.8 and a cross section of 7.37 × 10^-24 cm³ s^-1. The 20 TeV WIMP mass scenario, on the contrary, barely fits the data below 50 GeV, with a reduced χ² larger than 3 and ⟨ σv ⟩ = 2.72 × 10^-21 cm³ s^-1.