Dynamical Chirally Improved Quarks: First Results for Hadron Masses

We present first results for a study with two mass-degenerate dynamical Chirally Improved (CI) fermions on lattices of spatial extent 2.4 fm. The CI Dirac operator obeys the Ginsparg-Wilson condition in good approximation. The pion mass we use is still large O(470 MeV) for the 16**3*32 lattices with lattice spacing of 0.15 fm. The hadron masses are obtained with the variational technique and the results compared with earlier quenched calculations with similar lattice parameters. We find indications for the isovector, scalar meson a0(980) near the experimental value, in contradistinction to quenched results which always produced a mass value compatible with the first excitation a0(1450)