Light mass window of lepton portal dark matter

Understand

We explore a novel possibility that dark matter has a light mass below 1GeV in a lepton portal dark matter model.

• There are Yukawa couplings involving dark matter, left-handed leptons and an extra scalar doublet in the model.
• In the light mass region, dark matter is thermally produced via its annihilation into neutrinos.
• In order to obtain the correct relic abundance and avoid collider bounds, a neutral scalar is required to be light while charged scalars need to be heavier than the electroweak scale.