MECHANISM FOR ORDINARY STERILE NEUTRINO MIXING - ART. NO. 093017

Efficient oscillations between ordinary (active) and sterile neutrinos can occur only if Dirac and Majorana mass terms exist which are both small and comparable. It is shown that this can occur naturally in a c lass of string models, in which higher-dimensional operators in the su perpotential lead to an intermediate scale expectation value for a sca lar field and to suppressed Dirac and Majorana fermion masses. [S0556- 2821(98)07521-3]