Implications of a light dark Higgs solution to the gμ-2 discrepancy

A light scalar phi with mass less than or similar to 1 GeV and muonic coupling O(10(-3)) would explain the 3.5 sigma discrepancy between the Standard Model (SM) muon g - 2 prediction and experiment. Such a scalar can be associated with a light remnant of the Higgs mechanism in the dark sector. We suggest phi -> l(+)l(-) bump hunting in mu -> e nu(nu) over bar phi, mu(-)p -> nu(mu)n phi (muon capture), and K-+/- -> mu(+/-)nu phi decays as direct probes of this scenario. In a general setup, a potentially observable muon electric dipole moment less than or similar to 10(-23) e cm and lepton-flavor-violating decays tau -> mu(e)phi or mu -> e phi. can also arise. Depending on parameters, a deviation in BR (H -> mu(+)mu(-)) from SM expectations, due to Higgs coupling misalignment, can result. We illustrate how the requisite interactions can be mediated by weak-scale vector-like leptons that typically lie within the reach of future LHC measurements.