Proposal:

Add two data members to the class StDb/idl/VertexCuts.idl and consequently the offline database table Calibrations/tracker/PrimaryVertexCuts:

 float   ZMin;             // Min z of possible vertex positions
 float   ZMax;             // Max z of possible vertex positions

These will be used by vertex finders to restrict the allowable range in z for vertex searching and positions. It is up to the individual vertex finders to implement usage of these varaibles.

Example need:

The Minuit vertex finder has traditionally used a hardwired limit of |z|<200 cm. The fixed target program would like to use this vertex finder, but extend its range to z beyond -210 cm, where the fixed target was installed. Using the new database table parameters, vertex-finding can be tuned specifically for their data production without affecting any other productions.

The Minuit code can use ZMin == ZMax (as would be returned for old table entries in the database where these variables were not filled) as a condition to fall back to its historical defaults of -200,+200 cm.


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-Gene