  We consider current statistics for a two species exclusion process of
particles hopping in opposite directions on a one-dimensional lattice. We
derive an exact formula for the Green's function as well as for a joint current
distribution of the model, and study its long time behavior. For a step type
initial condition, we show that the limiting distribution is a product of the
Gaussian and the GUE Tracy-Widom distribution. This is the first analytic
confirmation for a multi-component system of a prediction from the recently
proposed non-linear fluctuating hydrodynamics for one dimensional systems.
