  The directed flow of particles produced in ultrarelativistic heavy ion
collisions at SPS and RHIC is so small that currently available methods of
analysis are at the border of applicability. Standard two-particle and
flow-vector methods are biased by large nonflow correlations. On the other
hand, cumulants of four-particle correlations, which are free from this bias,
are plagued by large statistical errors. Here, we present a new method based on
three-particle correlations, which uses the property that elliptic flow is
large at these energies. This method may also be useful at intermediate
energies, near the balance energy where directed flow vanishes.
