The three flavour chiral phase transition with an improved quark and gluonaction in lattice QCD

The finite-temperature chiral phase transition is investigated for three fl avours of staggered quarks on a lattice of temporal extent N-tau = 4. In th e simulation we use an improved fermion action which reduces rotational sym metry breaking of the quark propagator ( p4-action), include fat-links to i mprove the flavour symmetry and use the tree level improved (1,2) gluon act ion. We study the nature of the phase transition for quark masses of ma = 0 .025, ma = 0.05 and ma = 0.1 on lattices with spatial sizes of 8(3) and 16( 3).