First Step: I run the big full chain to create MuDst

root4star -b -q 'bfc.C(100,"DbV20101213 P2010a pmdReco btof BEmcChkStat Corr4 OSpaceZ2 OGridLeak3D","/star/data03/daq/2010/074/11074051/st_physics_11074051_raw_4040001.daq")'

Second Step: I create a separate directory, and adjust the alignment parameters by editing the files
under StarDb/Geometry/tpc by 0.02.

    row.innerSectorRotationAngle =          -0.00316107+0.02
    row.outerSectorRotationAngle =          -0.01077670+0.02

Third Step: Then I re-run the same bfc and get a new MuDst and compare agains the previous result.

In the comparation I used the charge, phi and pt for trajectories in the same TPC sector. 

We match the informations using trajectories of same charge and adopting charge equal and

the trajectory phi in a 0.05 window. Bellow we have the result as a function of pt.

 Figure 1

dpt = (pt1-pt2)/(q*pt)^2  where pt1 is the pt for the trajectories with the original alignment and pt2 with the alignment changed by 0.02.

 Conclusion: For pt > 0.6GeV we have approximately a constant behavior around 0.4 and for pt bellow 0.6GeV we see a dramatical behavior.