PrefaceF. Antinori, S. Bass, A. de Falco, C. Kuhn, M. Nardi, T. Peitzmann, T. Ullrich, J. Velkovska and U.A. WiedemannEur. Phys. J. C, 49 1 (2007) 1DOI: https://doi.org/10.1140/epjc/s10052-006-0190-6