Multi-Higgs Doublet Model: Can It Account for l^+l^-γγEvents?

Abstract

Motivated by recent experiments at LEP ($Z\to l^{+}{l}^{-}\gamma \gamma$, with $M_{\gamma \gamma }\simeq 59GeV$), we examine the possibility that such events are explained by a Bjorken process with a resonant Higgs ($M_{h^o}\simeq 59GeV$) decaying to $\gamma \gamma$. Our model is an N-doublet-Higgs model without CP-violation. Under the simplifying assumption that $(N-k)$ doublets ($k\ge 1$) decouple from the fermion sector, we could explain the observed events if: i) $(N-1)\ge 2$ and ii) the masses of the corresponding $(N-1)$ neutral scalars are either completely or almost degenerate, i.e. the decay $Z\to l^{+}{l}^{-}\gamma \gamma$ proceeds now via several overlapping resonances.

10 pages