Search for anomalous couplings in the Higgs sector at LEP

TL;DR

This study searches for Higgs bosons with anomalous couplings at LEP, analyzing multiple production and decay channels, and sets limits on anomalous couplings and partial decay widths due to no observed evidence.

Contribution

It provides the first experimental limits on anomalous Higgs couplings and decay widths in the specified mass range at LEP energies.

Findings

No evidence for anomalous Higgs production was observed.

Limits were set on anomalous couplings d, d_B, Delta g_1^Z, Delta kappa_gamma.

Constraints on partial decay widths Gamma(H -> gamma gamma) and Gamma(H -> Z gamma) were established.

Abstract

We search for a Higgs particle with anomalous couplings in the e+e- -> H gamma, e+e- -> HZ and e+e- -> He+e- processes with the L3 detector at LEP. We explore the mass range 70GeV < m_H < 170GeV using 176pb^-1 of integrated luminosity at a center-of-mass energy of \sqrt{s} = 189GeV. The Higgs decays H -> bb, H -> gamma gamma and H -> Z gamma are considered in the analysis. No evidence for anomalous Higgs production is found. This is interpreted in terms of limits on the anomalous couplings d, d_B, Delta g_1^Z and Delta kappa_gamma. Limits on the Gamma(H -> gamma gamma) and Gamma(H -> Z gamma) partial widths in the explored Higgs mass range are also obtained.