Signatures of anomalous Higgs couplings in angular asymmetries of H→Zℓ⁺ℓ^- and e⁺e^-→HZ

Parametrizing beyond Standard Model physics by the SU(3)×SU(2)_L×U(1)_Y dimension-six effective lagrangian, we study the impact of anomalous Higgs couplings in angular asymmetries of the crossing symmetric processes H→Zℓ⁺ℓ^- and e⁺e^-→HZ. In the light of present bounds on d = 6 couplings, we show that some asymmetries can reveal BSM effects that would otherwise be hidden in other observables. The d=6 HZγ couplings as well as (to a lesser extent) HZℓℓ contact interactions can generate asymmetries at the several percent level, albeit having less significant effects on the di-lepton invariant mass spectrum of the decay H→Zℓ⁺ℓ^-. The higher di-lepton invariant mass probed in e⁺e^-→HZ can lead to complementary anomalous coupling searches at e⁺e^- colliders.