Phase structure of one-flavour QCD

Abstract

Abstract Phase structure of one-flavour QCD C. Alexanch-ou a, 1, A. Borici b, A. Feo a, Ph. de Forcrand c, A. Galli d, F. Jegerlehner e, T. Takaishi f a Department of Natural Sciences, Unh,ersity of Cyprns, CY-1678 Nicosia, Cypnls b Paul Scherrer Institute, CH-5232 Villigen, Switzerland c Swiss Center for Scientific Computing, ETH-Zentnml, CH-8092 Ziirich, Switzerland d ELCA b~formatique, Hofiviesen Str. 26, CH-8057 Ziirich, Switzerland e DESY-IfH Zeuthen, D-15738 Zeuthen, Germany f Hiroshbna University of Economics, 731-01 Hiroshhna, Japan We present a study of the deconfinement phase transition of one-flavour QCD, using the multiboson algorithm [1]. The mass of the Wilson fermions relevant for this study is moderately large and the non-Hermitian multiboson algorithm [2] is a very suitable simulation algorithm. Finite size scaling is studied on lattices of size 83 x 4, 123 x 4 and 163 x 4. For heavy quarks, the behaviour of observables that probe the phase change, such as the Polyakov loop susceptibility, transition. The first-order transition weakens as the quark mass decreases and turns into a crossover. Locating the end-point (/~ep,/¢ep) accurately requires very large lattice sizes, beyond our computer capabilities. We thus consider an effective model, in the same universality class as full QCD but cheaper to simulate. By simulating larger systems, we locate the end-point in the coupling plane of this model. Then we map this end-point back onto full QCD. We thus estimate the end point of the first-order phase transition to occur at a quark mass of about 1.4 GeV. © 1999 Elsevier Science B.V. All rights reserved.