Residual third-body Coulomb effect on identical charged pion correlations in Au+Au collisions at STAR

We report the identical charged pion femtoscopic correlations measured by the STAR experiment in Au+Au collisions at √sNN = 3.0, 3.2, 3.5, 3.9, 4.5, 5.2, and 7.7 GeV. A clear collision energy dependence of the difference between π+π+ and π-π- correlations is observed for Rside and Rlong radii. Further study suggests the residual third-body Coulomb effect is the dominant source causing the difference.