Virtual Internal Bremsstrahlung of Dark Matter and Connection with AMS-02 Result

We consider a characteristic gamma-ray signal coming from Virtual Internal Bremsstrahlung of real scalar Dark Matter, which is the leading process of photon emission generated by Dark Matter annihilation. The signal can be consistent with the observed relic density of Dark Matter because of the strong suppression of the 2-body annihilation. Relation between the strong gamma-ray signal and the recent positron excess of AMS-02 is also discussed. A large s-wave of Dark Matter annihilation cross section is required to generate such a positron excess. This is achieved by taking into account both of left and right chiral couplings of Yukawa interaction.