How to use the Geogebra APP
- Fitting tracks with circles: click on the "Show He circle" check box and move the point on the circle to fit the Helium track. Repeat the same for the remaining two tracks (incoming pion and scattered pion). WARNING: the radius is really sensitive to small changes in the position of the point. So be careful and do your best to pass through the dark grey spots similar to those shown in the picture below!