Alignment and Position Calibration

 The radial scale of the FDC track centroid sets the angular scale for the forward detector. It's been checked with single muons. The first reference point is muon system the second is the vertex position Vertex position is calibrated with central muons .
Residue of the z position of the corrected reconstructed vertex from the z position of central muon tracks at the beam, as a function of the vertex z position. The solid line is a fitted straight line and the dashed line is delta z = 0.
Residue of the radial position of the FDC track centroid from the predicted radial position of forward muon tracks at the FDC, as a function of the track radial position. The solid line is a fitted proportionality line.

The EC's are aligned in the transverse directions with respect to the FDC's using the electrons from the W sample.

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