  We study the transport of the fermions with a small mass in the presence of
Coulomb impurities, which could be realized in slightly distorted Dirac
semimetals. Using the semiclassical Boltzmann equation, we derive the
relaxation times for two kinds of intra-cone transition process. One is due to
the effect of mass, and the other is due to the excited states in Landau levels
under the weaker magnetic field. Hence we derive the mass dependence and the
magnetic field dependence of the longitudinal magnetoconductivity in the
presence of parallel electric and magnetic fields.
