Phenomenological constraints on light mixed sneutrino WIMP scenarios

Scenarios where left- and right-handed sneutrinos mix and the lightest mixed one act as a thermal dark matter candidate can solve the dark matter, neutrino mass, and hierarchy problems simultaneously. We focus on the dark matter mass region of the order of 1 GeV, where dark matter direct detections are insensitive. We calculate the decay rate of a false vacuum induced by a large sneutrino trilinear coupling as well as other observables constrained by experiments. As a result, we show that there is an allowed region where the mass of the lightest neutralino is around 1 GeV. The allowed region can be tested by the search for the Higgs boson invisible decay at future colliders.