Searches for neutral Higgs bosons in ${\mathrm e}^+{\mathrm e}^-$ collisions around $\sqrt{s}$ = 189 GeV

Abstract.

Searches for neutral Higgs bosons in the Standard Model and the MSSM have been performed using data collected by the DELPHI experiment at a centre-of-mass energy of 188.7 GeV, corresponding to an integrated luminosity of 158 pb $^{-1}$ . These analyses are used, in combination with our results from lower energies, to set new 95% confidence level lower mass bounds on the Standard Model Higgs boson (94.6 GeV/ $c^2$ ) and on the lightest neutral scalar (82.6 GeV/ $c^2$ ) and neutral pseudoscalar (84.1 GeV/ $c^2$ ) Higgs bosons in a representative scan of the MSSM parameters. The results are also interpreted in the framework of a general two-Higgs doublet model.

Received: 14 February 2000 / Revised version: 10 March 2000 / Published online: 8 September 2000