  Using recently developed techniques for computing event shapes with
Soft-Collinear Effective Theory, LEP event shape data is used to derive strong
model-independent bounds on new colored particles. In the effective field
theory computation, colored particles contribute in loops not only to the
running of alpha_s but also to the running of hard, jet and soft functions.
Moreover, the differential distribution in the effective theory explicitly
probes many energy scales, so event shapes have strong sensitivity to new
particle thresholds. Using thrust data from ALEPH and OPAL, colored adjoint
fermions (such as a gluino) below 51.0 GeV are ruled out to 95% confidence
level. This is nearly an order-of-magnitude improvement over the previous
model-independent bound of 6.3 GeV.
