arXiv:nucl-ex/9607012v1 19 Jul 1996 CRITICAL BEHAVIOUR IN PERIPHERAL Au + Au COLLISIONS AT 35 MeV/u M. Bruno 1 , P. F. Mastinu 1,3 , M. Belkacem 1,9 , M. D’Agostino 1 , P. M. Milazzo 1,2 , G. Vannini 2 , D. R. Bowman 7 , J. D. Dinius 6 , A. Ferrero 4,8 , M. L. Fiandri 1 , C. K. Gelbke 6 , T. Glasmacher 6 , F. Gramegna 5 , D. O. Handzy 6 , D. Horn 7 , W. C. Hsi 6 , M. Huang 6 , I. Iori 4 , G. J. Kunde 6 , M. A. Lisa 6 , W. G. Lynch 6 , G. V. Margagliotti 2 , C. P. Montoya 6 , A. Moroni 4 , G. F. Peaslee 6 , R. Rui 2 , C. Schwarz 6 , M. B. Tsang 6 , C. Williams 6 , V. Latora 9 and A. Bonasera 9 1 Dipartimento di Fisica and INFN, Bologna, Italy 2 Dipartimento di Fisica and INFN, Trieste, Italy 3 Dipartimento di Fisica, Padova, Italy 4 Dipartimento di Fisica and INFN, Milano, Italy 5 INFN, Laboratori Nazionali di Legnaro, Italy 6 NSCL, Michigan State University, USA 7 Chalk River Laboratories, Chalk River, Canada 8 On leave from CNEA, Buenos Aires, Argentina 9 INFN, laboratorio Nazionale del Sud, Catania, Italy The signals theoretically predicted for the occurrence of a critical behavior (condi- tional moments of charge distributions, Campi scatter plot, fluctuations of the size of the largest fragment, power law in the charge distribution, intermittency) have been found for peripheral events in the reaction Au+Au at 35 MeV/u. The same signals have been studied with a dynamical model which foresees phase transition, like the Classical Molecular Dynamics. 1 Introduction The liquid-gas phase transition in nuclear systems has been recently theoret- ically and experimentally investigated 1,2,3 . In this contribution we report on the search for critical behavior signals in the experimental data of the Au + Au reaction at 35 MeV/u. The experiment was performed at the National Superconducting Cyclotron Laboratory of the Michigan State University tak- ing advantage of the coupling of the Multics 4 and the Miniball 5 apparatus. The analysis has been restricted to events corresponding to peripheral and semi-peripheral reactions, selected imposing that the component of the veloc- ity of the largest fragment along the beam direction was greater than 75% of the beam velocity and that the total detected charge was between 70 and 90. Most of these events come from the disassembly of the quasi-projectile, since the detection of the quasi-target is suppressed due to the thresholds of the detectors. Comparisons with the results of calculations in the framework of Classical 1