https://doi.org/10.1140/epjc/s2005-02122-4
experimental physics
Flavour-independent h0A0 search and two Higgs doublet model interpretation of neutral Higgs boson searches at LEP
Upper limits on the cross-section of the pair-production process 
, assuming 100 
branching fraction to hadrons, are derived from a new search for the 
hadrons final state, independently of the hadronic flavour of the decay products. This study, combined with previously published searches for the neutral Higgs bosons h0 and A0, is used to constrain the Type II Two Higgs Doublet Model (2HDM(II)) with no CP violation in the Higgs sector and no additional non-Standard Model particles besides the five Higgs bosons. The analysis combines LEP1 and LEP2 data collected with the OPAL detector up to the highest available centre-of-mass energies. The searches are sensitive to the 
and 
decay modes of the Higgs bosons. A benchmark scan of the 2HDM(II) parameter space is performed. Large regions of the 2HDM(II) parameter space explored are excluded at the 95% CL in the (
and 
planes, using both direct neutral Higgs boson searches and indirect limits derived from Standard Model high precision measurements. The region 
GeV and 
GeV is excluded at 95 % CL, independently of 
and for selected values of 
which are representative of a complete -scan.
© Springer-Verlag, 2005
