  An investigation of the critical behavior of strongly interacting QCD matter
has been performed by analyzing fluctuation observables on event-by-event (ebe)
basis measured in high-energy collision experiments. The fluctuation analysis
is performed using nuclear interactions at different target sizes and at
different colliding beam energies as a function of varying width of
pseudorapidity interval. For the sake of comparison, event-by-event
multiplicity fluctuations in hadronic and heavy-ion collisions (p-H, p-A and
A-B) are studied within the framework of the Lund Monte Carlo based FRITIOF
model. Charged particle multiplicity and the variance of the multiplicity
distribution are estimated for the interactions involving different target
sizes and beam momenta i.e., p-H, p-CNO, p-AgBr at 200A GeV/c and $^{16}$O-AgBr
collisions at 14.6, 60 and 200A GeV/c. Further, multiplicity fluctuations are
quantified in terms of intensive quantity, the scaled variances $\omega$ and
the strongly intensive quantity $\Sigma_{FB}$ derived from the charged particle
multiplicity and the width of the multiplicity distribution. Strongly intensive
quantity $\Sigma_{FB}$ is a quantity of great significance to extract
information about short and long-range multiplicity correlations. Furthermore,
the collision centrality and centrality bin width dependent behavior of the
multiplicity fluctuation have been examined in the framework of Lund Monte
Carlo based FRITIOF model. Results based on the fluctuation analysis carried
out in the present study are interpreted in terms of dynamics of collision
process and the possibility of related QCD phase transition.
