Hadronization during quark-gluon plasma phase transition

The hadron multiplicity distributions and factorial moments are studied in the framework of Landau theory of phase transitions. The factorial moments show a scaling law with a scaling exponent ν which characterizes the intermittency properties of the hadron phase for T<Tc (or Tt) where Tc (or Tt) is the transition temperature for second (or first) order transition. The scaling exponent ν is weakly dependent on the free energy parameters as well as on temperature. It is shown that ν remains practically constant in the hadron phase for which T<Tc or T<Tt whether the transition is second order or first order of second kind where the free energy expansion includes cubic term. This universality in the scaling exponent is also maintained above Tc over a wide range of temperature even if the transition is strongly first order of first kind where the free energy expansion has only even order coefficients, except around the critical temperature Tt where Tt approx-gt Tc. Therefore, the scaling exponent ν is rather more universal and only indicates the presence of a possible phase transition. It is further shown that the hadron multiplicity distribution is quite sensitive to the free energy parameters. The study of hadron multiplicity distribution at various resolution or bin size reveals more information about the dynamics of the phase transition. The calculated hadron multiplicity distributions are also compared with the negative binomial distribution, often used to explain the experimental multiplicity distributions. copyright 1996 The American Physical Society