  Spin-polarized metastable atoms of ultracold ytterbium are trapped at high
density and their inelastic collisional properties are measured. We reveal that
in collisions of Yb(3P2) with Yb(1S0) there is relatively weak inelastic loss,
but with a significant spin-dependence consistent with Zeeman sublevel changes
as being the dominant decay process. This is in strong contrast to our
observations of Yb(3P2)-Yb(3P2) collisional loss, which are, at low field, much
more rapid and have essentially no spin dependence. Our results give a
guideline to use the 3P2 states in many possible applications.
