Light hadron spectroscopy with O(a) improved dynamical fermions - art. no.034507.

We present the first results for the static quark potential and the light h adron spectrum using dynamical fermions at beta = 5.2 using an O(a) improve d Wilson fermion action together with the standard Wilson plaquette action for the gauge part. Sea quark masses were chosen such that the pseudoscalar -vector mass ratio, m(PS)/m(V), varies from 0.86 to 0.67. Finite-size effec ts are studied by using three different volumes 8(3) X 24, 12(3) X 24, and 16(3) X 24. Comparing our results to previous ones obtained using the quenc hed approximation, we find evidence for sea quark effects in quantities suc h as the static quark potential and vector-pseudoscalar hyperfine splitting . [S0556-2821(99)00613-X].