If quarks are composite particles then excited states are expected. 
We have searched in p-pbar collisions for excited quarks (q*) which decay to 
common quarks by emitting a W boson (q* -> qW) or a photon (q* -> q gamma). 
The simplest model of excited quarks has been excluded for mass M* < 540 GeV/c^2
at 95% confidence level.