Golden probe of the top Yukuwa coupling

We perform a preliminary study of the ability of the Higgs decay to four leptons to shed light on the top quark Yukawa couplings. In particular we examine whether the h →4 ℓ "golden channel" is sensitive to the C P properties of the top quark couplings to the Higgs boson. We show that kinematic distributions are sensitive to interference of the next-to-leading order electroweak corrections with the tree level Z Z contribution. This translates into a sensitivity to the top quark Yukawa couplings such that meaningful constraints on their C P properties can begin to be obtained once ∼300 fb^-1 of data has been collected at ∼14 TeV , with significant improvements at higher luminosity or with a higher energy hadron collider. This makes the h →4 ℓ channel a useful probe of the top quark Yukawa couplings that is qualitatively different from already established searches in h →V γ two body decays, t t h , and g g →h . We also briefly discuss other potential possibilities for probing the top Yukawa C P properties in h →2 ℓγ and ^ℓ+ℓ-→h Z ,h γ .