Revisiting the number-theory dark matter scenario and the weak gravity conjecture

摘要

We revisit the number-theory dark matter scenario where one of the light chiral fermions required by the anomaly cancellation conditions of U(1)(B_L) explains dark matter. Focusing on some of the integer B-L charge assignments, we explore a new region of the parameter space where there appear two light fermions and the heavier one becomes a dark matter of mass less than or similar to O(10) keV or O(10) MeV. The dark matter radiatively decays into neutrino and photon, which can explain the tantalizing hint of the 3.55 keV X-ray line excess. Interestingly, the other light fermion can erase the AdS vacuum around the neutrino mass scale in a compactification of the standard model to 3D. This will make the standard model consistent with the AdS-WGC statement that stable non-supersymmetric AdS vacua should be absent. (C) 2019 The Author(s). Published by Elsevier B.V.