Radiative Neutrino Mass Generation and Dark Matter - Institute for ...

Concrete ModelCoannihilation of DMCoannihilation of DMIf N 2 is degenerated with N 1 (M 1 ≈ M 2 ), they can coannihilate:The effective annihilation cross section σ eff includesN 1 N 2 → l α l β , N 2 N 2 → l α l β .s-wave appears due to the coannihilation processN 1 N 2 → l α l β if the Yukawa h αi are complex.σ eff v = a eff +b eff v 2 , a eff ∝ Im(h ∗ 1h 2 ) ≠ 0.→ It is possible to be consistent with LFV and DM relic abundance.Takashi Toma (IPPP) Internal Seminar 7th June 2013 20 / 34