The task is, given a set of tracks, to compute the best estimate of the vertex parameters (position, covariance matrix, constrained track parameters and their covariances) as well as indicators of the fit success (total chi^2, number of degrees of freedom, track weights). If so designed, it can decides which track to use and with which weight.
Vertex fitting proceeds in several steps, controlled by the VertexFitter. Internally, these steps are implemented in several algorithm classes, which use intermediate reconstructed objects internally. Vertex fitting algorithms are configured with the algorithm which is suited to their needs, so that users should not have to worry about a proper choice. These classes are only used internally by the VertexFitter and are not meant to be used directly. The algorithm classes and internal objects are described further in this section.
Steps 2-4 are repeated until of the vertex position and covariance matrix converge.
The main components of vertex fitting are:
Internal reconstruction objects:
Editor/Reviewer | Comments |
---|---|
Main.speer - 18 Jul 2006 | Page author |
JennyWilliams - 28 Mar 2007 | edited for inclusion in swguide |
Responsible: Main.speer (Thomas Speer)
Last reviewed by: Reviewer