Analyses of two and three pion Bose-Einstein Correlations using Coulomb wave functions

Using effective formulas we analyze the Bose-Einstein correlations (BEC) data corrected for Coulomb interactions provided by STAR Collaboration and the quasi-corrected data (raw data with acceptance correction etc) on 2\pi and 3\pi BEC by using Coulomb wave function with coherence parameter included. The corresponding magnitudes of the interaction regions turn out to be almost the same: R_{Coul}(2\pi) \simeq \frac 32R_{Coul}(3\pi). R_{Coul} means the size of interaction region obtained in terms of Coulomb wave function. This approximate relation is also confirmed by the core-halo model. Moreover, the genuine 3rd order term of BEC has also been investigated in this framework and its magnitude has been estimated both in the fully corrected data and in the quasi-corrected data.