ABSTRACT
The adiabatic conversion of solar electron neutrinos to muon neutrinos via the Mikheyev-Smirnov-Wolfenstein mechanism is discussed as a level-crossing problem. Solutions to the 37Cl puzzle obtained numerically by Mikheyev and Smirnov, Rosen and Gelb, and others are shown to form the boundary of the region in the δm 2-sin22θ plane where adiabatic conversion occurs. Most of the region within this boundary is ruled out by the nonzero signal in Davis’s experiment. The Landau-Zener description of the adiabatic boundary is employed.
