5.8 Y'/Z Projection

If one views an event perpendicular to the beam axis, some tracks are curved and some are straight, depending on the azimuthal angle φ VIEW of the viewing direction. Such a projection is of use only if a sufficiently narrow jet is selected, which may even consist of a single track. In this case a jet based Cartesian coordinate system is optimal, which depends on the direction of the jet axis:

In the Y'/Z projection a single track has maximal curvature and minimum angle to the Z axis. Seen with stereo it would leave the plane towards the observer or opposite. The track is seen from the same side as in the Y/X projection (see 5.1 Y/X Projection) only rotated around the Y' axis. This projection provides a second intuitively understandable view of the region around the primary vertex orthogonal to that of the X'/Z projection (see 5.7 X'/Z Projection). The momentum of tracks may not be estimated form their curvature in this projection.

The calorimeters and the muon chamber barrels cannot be displayed as they would overlap the inner tracking detectors. The endcaps can be drawn.

An alternative to Y'/Z is the expert φ/Z projection (see 5.6 φ/Z Projection), which is not limited to single jets.

The Y'/Z Projection Menu (see 3.3.2 Projection Menus)