Very light Higgs bosons in extended models at the LHC

Abstract

The Large Electron-Positron (LEP) collider experiments have constrained the mass of the standard model (SM) Higgs boson to be above 114.4 GeV. This bound applies to all extensions of the SM where the coupling of a Higgs boson to the $Z$ boson and also the Higgs decay profile do not differ much from the SM one. However, in scenarios with extended Higgs sectors, this coupling can be made very small by a suitable choice of the parameters of the model. In such cases, the lightest $CP$-even Higgs boson mass can in turn be made very small. Such a very light Higgs state, with a mass of the order of the $Z$ boson one or even smaller, could have escaped detection at LEP. In this work we perform a detailed parton level study on the feasibility of the detection of such a very light Higgs particle at the Large Hadron Collider (LHC) in the production process $pp\ensuremath{\rightarrow}hj\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}j$, where $j$ is a resolved jet. We conclude that there are several models where such a Higgs state could be detected at the LHC with early data.