  While yields of Sigma0 have been measured in many different colliding
systems, no measurements exist in high energy nuclear collisions. It also
remains unexplored whether the relative yields of Sigma0 and Lambda change in
collisions of heavy ions where a dense medium may permit alternate production
mechanisms, such as quark coalescence. The STAR detector at RHIC is able to
reconstruct the electromagnetic Sigma0 decay into Lambda plus gamma via the
weak decay of the Lambda and gamma conversions into e+e- pairs in the detector
material. We report here on our measurement of the ratio Sigma0/Lambda in
minimum bias 200 GeV d+Au collisions. We also compare the measured ratio to
expectations from various models.
