Units and Conventions

All energies are in GeV without exception. Angles are either represented in degree (the default) or in radians (optional). To switch between degrees and radians use the View->Show Radians menu item.

Angles are defined with respect to the incoming lepton beam as depicted in the figure below.

Note that there is no standard convention. Often the angle w.r.t. the proton is used which for example yields the well known expression:

In our case, however, the same equation reads

The convention used in eDISK is the one that was commonly used at Hera.