Search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model in e+e−interactions at s= 189 GeV

A search for the lightest neutral scalar and neutral pseudoscalar Higgs bosons in the Minimal Supersymmetric Standard Model is performed using 176.4 pb -1 of integrated luminosity collected by L3 at a center-of-mass energy of 189 GeV. No signal is observed, and the data are consistent with the expected Standard Model background. Lower limits on the masses of the lightest neutral scalar and pseudoscalar Higgs bosons are given as a function of tanβ. Lower mass limits for tanβ>1 are set at the 95% confidence level to be m h > 77.1 GeV and m A >77.1 GeV.