Search for anomalous couplings in the Higgs sector at LEP

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 < mH < 190 GeV is explored using 602 pb −1 of integrated luminosity collected wit the L3 detector at LEP at centre-of-mass energies √ s = 189–209 GeV. The Higgs decay channels H → ff̄, H → γ γ , H → Zγ 92 L3 Collaboration / Physics Letters B 589 (2004) 89–102 malous and H→ WW(∗) are considered and no evidence is found for anomalous Higgs production or decay. Limits on the ano couplingsd, dB , g Z 1 , κγ andξ 2 are derived as well as limits on the H → γ γ and H→ Zγ decay rates.  2004 Published by Elsevier B.V. akthe d s an len is om lous