LATTICE QCD WITH SMALL NUMBER OF FLAVOURS
A. Irb\"ack, F. Karsch, B. Petersson and H.W. Wyld
Abstract: The finite temperature behaviour of lattice QCD with dynamical
quarks for small number of flavours $N_f$ is investigated. Simulations
have been performed on lattices of size $N_\sigma^3\cdot 4$ with
$N_\sigma=8$ and 12 and staggered fermions of mass $ma=0.1$ using a
hybrid algorithm. We find that the two state signal at the critical
point of the pure gauge theory, which is taken as a sign for a first
order phase transition, persists for the values of $N_f$ we have
investigated, namely $N_f=0.5$, 1 and 2. It is, however, considerably
weaker for $N_f=1$ and 2. Moreover, for $N_f=2$ the discontinuity at
$\beta_c$ decreases with increasing lattice size. This puts doubt on the
first order nature of the $N_f=2$ transition at intermediate mass.