  Quantum Chromodynamics (QCD) is a basic gauge field theory to describe strong
interactions. Lattice QCD calculations predict a phase transition from hadronic
matter to a deconfined, locally thermalized Quark-Gluon Plasma (QGP) state at
high temperature and small baryon density. Plenty of exciting results from RHIC
experiments in the first three years have demonstrated that a hot dense matter
with strong collective motion which cannot be described with hadronic degrees
of freedom was created at RHIC. Charm quarks are believed to be mostly created
from initial gluon fusion in heavy ion collisions. Since they are massive,
charm hadrons are proposed to be ideal probes to study the early stage dynamics
in heavy ion collisions.
  We provide here an indirect measurement of charm semi-leptonic decay. Single
electron transverse momentum ($p_T$) distributions from 200 GeV \dAu, \pp
collisions and 62.4 GeV \AuAu collisions, and single electron azimuthal
anisotropy ($v_2$) from 62.4 GeV \AuAu collisions are presented. (Abridged)
