EFFECT OF OFF-DIAGONAL PARTON DISTRIBUTIONS IN DIFFRACTIVE VECTOR MASON ELECTROPRODUCTION

We present a simple physical description of the off-diagonal gluon dis tribution g(x,x',Q(2)) and splitting function P-gg(x,x') which enter t he amplitude for diffractive vector mason production. We study the off -diagonal effects both on the evolution in Q(2) and on the input distr ibution. We predict the ratio R of the off-diagonal to the diagonal gl uon density, x'g(x,x',Q(2))/xg(x,Q(2)), as a function of the kinematic variables.