Figure 1
Plot: M. Aguilar et al. [1]; Grey region, see Ref. [4]

Figure 1: The positron fraction in high-energy cosmic rays. The new measurement from the AMS extends over a wider energy range and has much lower uncertainty than the earlier measurements from the PAMELA and Fermi-LAT satellites (or older balloon experiments). The AMS measurement confirms an excess in the high-energy positron fraction, above what is expected from positrons produced in cosmic-ray interactions. (The grey band indicates the expected range in the positron fraction, which is based on calculations in Ref. [4].)