Higgs to Four Taus at ALEPH

TL;DR

This paper reports a search for a Higgs boson decaying into four tau leptons via intermediate pseudoscalar particles using ALEPH data, setting limits on the production rate for Higgs masses between 70 and 114 GeV.

Contribution

It provides the first experimental limits on Higgs to four tau decays via pseudoscalars at LEP energies, constraining new physics models.

Findings

No excess above background observed.

Limits set on Higgs production cross-section times branching ratios.

Excluded parameter space for certain Higgs and pseudoscalar masses.

Abstract

A search has been performed on 683 pb$^{-1}$ of data collected by the ALEPH detector at the Large Electron-Positron (LEP), collider at centre-of-mass energies from 183 to 209 $\mathrm{GeV}$ looking for a Higgs boson decaying into four $\tau$ leptons via intermediate pseudoscalar $a$ particles, for a Higgs mass range of 70 to 114 $\mathrm{GeV} / c^2$ and an $a$ mass range of 4 to 12 $\mathrm{GeV} / c^2$. No excess above background is seen and a limit is placed on $\xi^2 = \frac{\sigma(e^+ e^-\ra Z+h)}{\sigma_{SM}(e^+ e^-\ra Z+h)}\times(h\ra aa)\times(a\ra \tau^+\tau^-)^2$ in the $m_h, m_a$ plane. For $m_h < 107 \; \mathrm{GeV} / c^2$ and $m_a < 10 \; \mathrm{GeV} / c^2$, $\xi^2 > 1$ can be excluded at the 95\% confidence level.