  The study of liquid-gas phase transition in heavy ion collisions has
generated a lot of interest amongst the nuclear physicists in the recent years.
In heavy ion collisions, there is no direct way of measuring the state
variables like entropy, pressure, energy and hence unambiguous characterization
of phase transition becomes difficult. This work proposes new signatures of
phase transition that can be extracted from the observables which are easily
accessible in experiments. It is observed that the temperature dependence of
the first order derivative of the order parameters in nuclear liquid gas phase
transition exhibit similar behavior as that of the variation of specific heat
at constant volume Cv which is an established signature of first order phase
transition. This motivates us to propose these derivatives as confirmatory
signals of liquid-gas phase transition. The measurement of these signals in
easily feasible in most experiments as compared to the other signatures like
specific heat, caloric curve or bimodality. Total multiplicity, size of largest
cluster are some of the order parameters which have been studied. Statistical
Models based on canonical ensemble and lattice gas model has been used for the
study. This temperature where the peak appears is designated to be the
transition temperature and the effect of certain parameters on this has also
been examined. The multiplicity derivative signature proposed in this work has
been further confirmed by other theoretical models as well as in experimental
study.
