Azimuthally differential femtoscopic measurements, being sensitive to
spatio-temporal characteristics of the source as well as to the collective
velocity fields at freeze-out, provide very important information on the nature
and dynamics of the system evolution. While the HBT radii modulations relative
to the second harmonic event plane reflect mostly the spatial geometry of the
source, the third harmonic results are mostly defined by the velocity fields.
Radii variations with respect to the third harmonic event plane unambiguously
signal a collective expansion and anisotropy in the flow fields. Read More