  The linear temperature dependence of the resistivity above the optimal doping
is a longstanding problem in the field of high temperature superconductivity in
cuprates. In this paper, we investigate the effect of gauge fluctuations on the
momentum relaxation time and the transport scattering rate within the slave
boson method. We use a more general slave treatment to resolve the ambiguity of
decomposing the Heisenberg exchange term. We conclude that this term should be
decomposed only in the Cooper channel. This results in the spinon mass
inversely proportional to the doping. It is showed that solving the equation
for the transport scattering rate self-consistently, we find a crossover
temperature above which we obtain the linear temperature dependence of the
electrical resistivity as well as the single particle scattering rate. It is
also shown that this linear temperature dependence of the scattering rate in
the pseudogap region explains the existence of the Fermi arcs with a length
that linearly varies with temperature.
