Laboratory for High Energy Astrophysics, Goddard Space Flight Center, Greenbelt, MD 20771

A new, non-resonant pitch-angle scattering process has been found, which very efficiently scatters the cosmic-ray particles through the zero pitch-angle cosine. Combining this process with the effects of gyroresonance and transit-time damping, I will fit the data of parallel mean free path as a function of particle rigidity obtained from measurements of cosmic rays during solar events. I will also discuss the resulting parameters of the solar wind turbulence on the path of the observed cosmic rays.