Chemical fluctuations in high-energy nuclear collisions

Fluctuations of the chemical composition of the hadronic system produced in nuclear collisions are discussed using the Phi-measure which has been earl ier applied to study the transverse momentum fluctuations. The measure is e xpressed through the moments of the multiplicity distribution and then the properties of Phi are discussed within a few models of multiparticle produc tion. A special attention is paid to the fluctuations in the equilibrium id eal quantum gas. The system of kaons and pions, which is particularly inter esting from the experimental point of view, is discussed in detail. (C) 199 9 Published by Elsevier Science B.V. All rights reserved.