An event display of a reconstructed B0 -> D*+D*-
actual data event within the
BaBar detector. Tracks (shown in purple) are
charged particles which cross the tracking volume (instrumented silicon layers and a wire chamber). The event is reconstructed using information
from the momenta of the tracks (seen via their curvature in the 1.5T magnetic field) and
the energies deposited in the (cesium-iodide) crystal calorimeter (seen as green rectangles).
