  A degenerate pump--probe technique is used to investigate the non equilibrium
carrier dynamics in multi--layer graphene. Two distinctly different dynamics of
the carrier relaxation are observed. A fast relaxation ($\sim 50$ fs) of the
carriers after the initial effect of phase space filling followed by a slower
relaxation ($\sim 4$ ps) due to thermalization. Both relaxation processes are
less efficient when a magnetic field is applied at low temperatures which is
attributed to the suppression of the electron-electron Auger scattering due to
the non equidistant Landau level spacing of the Dirac fermions in graphene.
