  I derive analytically the temporal dependence of the perpendicular transport
coefficient of a charged particle in the three-dimensional anisotropic
turbulence conjectured by Goldreich-Sridhar by implementing multi-spacecraft
constraints on the turbulence power spectrum. The particle motion away from the
turbulent local field line is assessed as gradient/curvature drift of the
guiding-center and compared with the magnetic field line random walk. At
inertial scales much smaller than the turbulence outer scale, particles
decorrelate from field lines in a free-streaming motion, with no diffusion. In
the solar wind at $1$ AU, for energy sufficiently small ($< 1$ keV protons),
the perpendicular average displacement due to field line tangling generally
dominates over two decades of turbulent scales. However, for higher energies
($\simeq 25$ MeV protons) within the range of multi-spacecraft measurements,
the longitudinal spread originating from transport due to gradient/curvature
drift reaches up to $\simeq 10^\circ- 20^\circ$. This result highlights the
role of the perpendicular transport in the interpretation of interplanetary and
interstellar data.
