Search for a Higgs Boson Decaying into Two Photons with the L3 Detector at LEP

TL;DR

This paper reports a search for a Higgs boson decaying into two photons using LEP data, setting limits on the decay and deriving a lower mass limit for a fermiophobic Higgs.

Contribution

The study provides the first limits on Higgs to two photon decay in the specified energy range using LEP data, including a lower mass limit for a fermiophobic Higgs.

Findings

No excess observed over background expectations.

Limits set on Higgs to two photon branching fraction.

Lower mass limit established for fermiophobic Higgs.

Abstract

A search is performed for a Higgs boson, decaying into two photons, using the L3 data collected at centre of mass energies between $\sqrt s$ = 189 and 202 GeV, corresponding to an integrated luminosity of 400 pb$^{-1}$. The processes $e^{+}e^{-}\to {Zh} \to {q} \bar{q} \gamma \gamma $, $e^{+}e^{-}\to {Zh} \to \nu \bar{\nu} \gamma \gamma $, $e^{+}e^{-}\to {Zh} \to {l}^{+} {l}^{-} \gamma \gamma $ are considered. The observed data are found to be consistent with the expected background from standard physics processes. Limits on the branching fraction of the Higgs boson decay into two photons as a function of the Higgs mass are shown and a lower mass limit on a fermiophobic Higgs is derived.