EARTH EFFECT IN THE MSW ANALYSIS OF THE SOLAR-NEUTRINO EXPERIMENTS

We consider the Earth effect in the combined Mikheyev-Smirnov-Wolfenst ein analysis of the solar neutrino experiments including theoretical u ncertainties. Using the time-averaged data, the allowed large-angle re gion extends to much smaller angles than when the Earth effect is igno red. However, the additional constraint from the Kamiokande II day-nig ht data excludes the parameter space most sensitive to the Earth effec t, leaving only a small large-angle region close to maximal mixing at 90% C.L. The nonadiabatic solution remains unaffected by the Earth eff ect and is still preferred.