Lepton-flavored dark matter

Abstract

In this work, we address two paradoxes. The first is that the measured dark-matter relic density can be satisfied with new physics at O(100 GeV–1 TeV), while the null results from direct-detection experiments place lower bounds of O(10 TeV) on a new-physics scale. The second puzzle is that the severe suppression of lepton-flavor-violating processes involving electrons, e.g. μ→3e, τ→eμμ, etc., implies that generic new-physics contributions to lepton interactions cannot exist below O(10–100 TeV), whereas the 3.6σ deviation of the muon g−2 from the standard model can be explained by a new-physics scale <O(1 TeV). Here, we suggest that it may not be a coincidence that both the muon g−2 and the relic density can be satisfied by a new-physics scale ≲1 TeV. We consider the possibility of a gauged lepton-flavor interaction that couples at tree level only to μ- and τ-flavored leptons and the dark sector. Dark matter thus interacts appreciably only with particles of μ and τ flavor at tree level and has loop-suppressed couplings to quarks and electrons. Remarkably, if such a gauged flavor interaction exists at a scale O(100 GeV–1 TeV), it allows for a consistent phenomenological framework, compatible with the muon g−2, the relic density, direct detection, indirect detection, charged-lepton decays, neutrino trident production, and results from hadron and e+e− colliders. We suggest experimental tests for these ideas at colliders and for low-energy observables.