Search for anomalous couplings in the Higgs sector at LEP

Abstract

Anomalous couplings of the Higgs boson are searched for through the processes e⁺e^-→ Hγ, e⁺e^-→e⁺e^-H and e⁺e^-→HZ. The mass range 70 GeV< m_H<190 GeV is explored using 602 pb^-1 of integrated luminosity collected with the L3 detector at LEP at centre-of-mass energies √ s=189-209 GeV. The Higgs decay channels H→ff̅, H→ γγ, H→Zγ and H →WW^∗are considered and no evidence is found for anomalous Higgs production or decay. Limits on the anomalous couplings d, d_B, Δg₁^Z, Δκ_γand ξ² are derived as well as limits on the H→γγand H→ Zγ decay rates.