We study QCD with two staggered Dirac fermions both in the fundamental (QCD)
and the adjoint representation (aQCD) near the chiral transition. The aim is to
find the universality class of the chiral transition and to verify Goldstone
effects below the transition. We investigate aQCD, because in that theory the
deconfinement and the chiral transitions occur at different temperatures
T_d<T_c. Here, we show that the scaling behaviour of the chiral condensate in
the vicinity of \beta_c is in full agreeement with that of the 3d O(2)
universality class. In the region T_d<T<T_c we confirm the quark mass
dependence of the chiral condensate which is expected due to the existence of
Goldstone modes like in 3d O(N) spin models. For fundamental QCD we use the
p4-action. Here, we find Goldstone effects below T_c like in aQCD and the 3d
O(N) spin models, however no O(2)/O(4) scaling near the chiral transition
point. The result for QCD may be a consequence of the coincidence of the
deconfinement transition with the chiral transition.Comment: 6 pages, 5 figures, poster contribution to Lattice 2005 (Nonzero
temperature and density), one reference added, figure 2 change
