  Motivated by recent development in time-resolved angle-resolved photoemission
spectroscopy (trARPES) for d-wave superconductors, we analyze the
non-equilibrium relaxation dynamics of the laser pulse excited sample within
the scenario of two-temperature model. It is shown that the main features
reported in the trARPES technique may be understood within this
phenomenological picture. The momentum dependence of the excited quasiparticle
density and the relaxation rate is associated with the dynamics of the nodal
d-wave superconducting gap, and the fluence dependence of the relaxation rate
is related to the recombination process of quasiparticles into Cooper pairs.
