Eur. Phys. J. C 27, 433-438 (2003)
DOI: 10.1140/epjc/s2002-01103-5

Comparing different hard-thermal-loop approaches to quark number susceptibilities

J.-P. Blaizot¹, E. Iancu^{1, 2} and A. Rebhan<sup>2, 3

1</sup>  Service de Physique Théorique, CE Saclay, 91191 Gif-sur-Yvette, France
²  Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA
³  Institut für Theoretische Physik, Technische Universität Wien, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria

(Received: 27 June 2002 / Revised version: 23 September 2002 / Published online: 31 January 2003 )

Abstract
We compare our previously proposed hard-thermal-loop (HTL) resummed calculation of quark number susceptibilities using a self-consistent two-loop approximation to the quark density with a recent calculation of the same quantity at the one-loop level in a variant of HTL-screened perturbation theory. Besides pointing out conceptual problems with the latter approach, we show that it severely over-includes the leading-order interaction effects, while including none of the plasmon terms, which is the main reason for requiring improved resummation schemes.

© Società Italiana di Fisica, Springer-Verlag 2003