  Recently a model for noisy reduced magnetohydrodynamic turbulence was
proposed. The latter model was already used to study the random walk of
magnetic field lines. In the current article we use the same model to
investigate the diffusion of energetic particles across the mean magnetic
field. To compute the perpendicular diffusion coefficient two analytical
theories are used, namely the Non- Linear Guiding Center (NLGC) theory and the
Unified Non-Linear Transport (UNLT) theory. It is shown that the two theories
provide different results for the perpendicular diffusion coefficient. We also
perform test-particle simulations for the aforementioned turbulence model. We
show that only the UNLT theory describes perpendicular transport accurately
confirming that the latter theory is a powerful tool in diffusion theory.
