  In this paper we present the measurement of charged pion two-particle
femtoscopic correlation functions in 200 GeV Au+Au collisions, in 31 average
transverse mass bins, separately for positive and negative pion pairs.
L\'evy-shaped source distributions yield a statistically acceptable description
of the measured correlation functions, with three physical parameters:
correlation strength parameter lambda, L\'evy index alpha and L\'evy scale
parameter R. The transverse mass dependence of these L\'evy parameters is then
investigated and their physical interpretation is also discussed, and the
appearance of a new scaling variable is observed.
