Measures of azimuthal correlations in relativistic heavy ion collisions

Based on the initial state geometrical symmetry for collisions between two identical heavy ions at high energy, the general form for the one- and two-particle azimuthal distributions is deduced. Relation between these distributions and the usual flow parameters is discussed. New measures for the azimuthal correlations are suggested. Some numerical results on the values of the measures are shown from an event generator for Au+Au collisions with different colliding centralities at 200 GeV.