Abstract
The creation of strongly interacting dense state of matter is expected in heavy-ion accelerators at relativistic energies, such as Relativistic Heavy Ion collider and Large Hadron Collider experiments. These experiments are believed to provide us the signature of the formation on quark-gluon plasma (QGP) and possible QCD phase transition. The charged particles directly and indirectly measured by detectors located near the collision point bear the signals of QGP and hint toward the occurrence of QCD phase transition going from hadronic phase to the QGP phase and vice versa. The observation of large particle density fluctuations in the JACEE experiment and its explanation by normalized factorial moments triggered investigations of multiplicity fluctuation patterns with decreasing domains of phase space (one-, two-, or three-dimensional phase space) invoked special interest to analyze such events. Fluctuations of dynamical origin are reflected in probability density as intermittency behavior and indicate toward the creation of QGP. Various fluctuation observables were proposed on theoretical basis, and their measurements became possible by the availability of detector facility in these modern and technologically rich experiments. A careful measurement and examination have been carried out over past years with many discoveries and are still in progress to address many new physics issues.