Signature of Granular Structures by Single-Event Intensity Interferometry

The observation of a granular structure in high-energy heavy-ion collisions can be used as a signature for the quark-gluon plasma phase transition, if the phase transition is first order in nature. We propose methods to detect a granular structure by the single-event intensity interferometry. We find that the correlation function from a chaotic source of granular droplets exhibits large fluctuations, with maxima and minima at relative momenta which depend on the relative coordinates of the droplet centers. The presence of this type of maxima and minima of a single-event correlation function at many relative momenta is a signature for a granular structure and a first-order QCD phase transition. We further observe that the Fourier transform of the correlation function of a granular structure exhibits maxima at the relative spatial coordinates of the droplet centers, which can provide another signature of the granular structure.