TPAR - track parameters banks

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Note: This is provisional

The track finding and fitting result in fitted track parameters for each found track. TPAR banks are created before vertex reconstruction so that the TPAR track parameters are fitted without vertex constraint.

The parameters are given at two different positions on the trajectory:

1. at the point of closest approach two the origin
2. at the intersection of the fitted trajectory and the plane of first measured point

The three momentum definition parameters are defined as:

Space position elements of the covariance matrix are not defined in terms of the components of , but rather in terms of parameters which measure the position precision in two mutually orthogonal directions transverse to the trajectory:

Notice that measures the impact parameter in xy plane. The position along the trajectory ( ) is taken as fixed for the covariance matrix. The relation between and these transverse parameters is given by:

The variance of is given by:

Notice that in GEANE package one uses the parameters (1/p, , , , ) referred there as system I.