  The search for particle electric dipole moments represents a most promising
way to search for physics beyond the standard model. A number of groups are
planning a new generation of experiments using stored gases of various kinds.
In order to achieve the target sensitivities it will be necessary to deal with
the systematic error resulting from the interaction of the well-known E x v
field with magnetic field gradients (often referred to as the geometric phase
effect [9,10]). This interaction produces a frequency shift linear in the
electric field, mimicking an edm. In this work we introduce an analytic model
for the correlation function which determines the behavior of the frequency
shift [11], and show in detail how it depends on the operating conditions of
the experiment. We also propose a method to directly measure ths correlation
function under the exact conditions of a given experiment.
