Last update:
Apr 1, 2000



Track Fitting on the Riemann Sphere

Are Strandlie^{1},
Jørn Wroldsen^{2}
 Department of Technology, Gjøvik College, and Department of Physics, University of Oslo.
 Department of Technology, Gjøvik College.
Speaker:
Jørn Wroldsen
We present a novel method of fitting trajectories of charged particles in
highenergy physics particle detectors. The method fits a circular arc to
twodimensional measurements by mapping the measurements onto the Riemann
sphere and fit a plane to the transformed coordinates of the measurements.
In this way, the nonlinear task of circle fitting, which in general requires
the application of some iterative procedure, is turned into a linear problem
which can be solved in a fast, direct and noniterative manner.
We illustrate the usefulness of our approach by stating results from
simulation experiments of tracks from the ATLAS Inner Detector Transition
Radiation Tracker (TRT). The experiments show that the accuracy of the estimated
track parameters is virtually as good as the accuracy obtained by applying an
optimal, nonlinear leastsquares procedure. The computational cost of our
method, however, is significantly lower.
Presentation:  Short Paper: 
