Event anisotropy measurements at RHIC suggest the strongly interacting matter created in heavy ion collisions flows with very little shear viscosity. Precise determination of shear viscosity-to-entropy ratio is currently a subject of extensive study. We present preliminary results of measurements of the evolution of transverse momentum correlation function with collision centrality of $Au +Au$ interactions at $sqrt{s_{NN}}$ = 200 GeV. We compare two differential correlation functions, namely {it inclusive} and a differential version of the correlation measure $tilde C$ introduced by Gavin ${it et. al.}$. These observables can be used for the experimental study of the shear viscosity per unit entropy.
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