PUB - Publikationen an der Universität Bielefeld

We discuss resummation strategies for free energy in quantum field theories at nonzero temperatures T. We point out that resummations should be performed for the short- and long-distance parts separately in order to avoid spurious interference effects and double counting. We then discuss and perform Pade resummations of these two parts for QCD at high T. The resummed results are almost invariant under variation of the renormalization and factorization scales. We perform the analysis also in the case of the massless scalar phi(4) theory.