LCD Tracking Problems

e+e- ->  Z Higgs  Large (L2) detector

  Run 1, Evt 1:  Badly drawn track, MCP #20

Found problem in HelicalSwimmer in which the track parameters were not being interpreted correctly. Both the curvature and xy distance of closest approach are signed quantities. Tracker versions 1.1.9 and higher have the problem fixed.


  Run 1, Evt 1:  Bad track parameters, MCP #61

The xy distance of closest approach, d0, is calculated to be less than 30 cm, but it appears that the closest approach is nearly 50 cm. A calculation of the center of the circle (C) and the radius of curvature (19.4 cm) gives the xy distance of closest approach to be 48 cm. Will use the difference in radii (dR) and the sign from the deviation from orbit (d0) for now.


  Run 1, Evt 1:  Partially drawn spiral, MCP #21-23

Found ...