  Electromagnetic field in heavy ion collisions are expected to cause charge
dependent directed flow splitting ($\Delta v_1$). Such charge dependent $\Delta
v_1$ has been observed by the STAR collaboration. We demonstrate that
relativistic dissipative fluid dynamic simulations with baryon diffusion that
include realistic model of baryon stopping in the initial condition and no
contribution from electromagnetic field describe the measured $\Delta v_1$ for
observables involving baryons and anti-baryons. This suggests strong background
contribution from baryon current as a response to initial state baryon
inhomogeneities to such charge dependent $\Delta v_1$ involving baryons and
anti-baryons. Our current model calculations that only account for the
evolution of the baryon charge and not electric charge and strangeness miss the
observed $\Delta v_1$ of mesons leaving their interpretation open.
