Nuclear Coulomb Field Effects in Two-Pion Bose-Einstein Correlations

Differences are investigated in pion source sizes derived using {pi}{sup +}{pi}{sup +} and {pi}{sup -}{pi}{sup -} pairs in the large statistics data set collected with the E866 Forward Spectrometer for central Au+Au collisions at 11.6 A. {center_dot} GeV/c in AGS Experiment E866. These differences in source radii are interpreted using a simple classical description for the Coulomb and the transverse-momentum (p{sub T}) dependent source radius parameters. An estimated effective net charge responsible for the distortion is considerably smaller than the expected total projectile participant protons, which suggests that the system undergoes a rapid expansion in the longitudinal direction before freezeout. This picture is consistent with the results derived from the {pi}{sup -}/{pi}{sup +} singles yield ratios for the same reactions