Anomalous multiplicity fluctuations from phase transitions in heavy-ion collisions - art. no. 064904

Event-by-event fluctuations and correlations between particles produced in relativistic nuclear collisions are studied. The fluctuations in positive, negative, total, and net charge are closely related through correlations. I n the event of a phase transition to a quark-gluon plasma, fluctuations in total and net charge can be enhanced and reduced, respectively, which, howe ver, is very sensitive to the acceptance and centrality. If the colliding s ystem experiences strong density fluctuations due, e.g., to droplet formati on in a first-order phase transition. all fluctuations can be enhanced subs tantially. The importance of fluctuations and correlations is exemplified b y event-by-event measurement of the multiplicities of J/Psi 's and charged particles since these observables should anticorrelate in the presence of c omover or anomalous absorption.