Add MvdHit errors

Add a fixed error of 8mum for the x- and y-position of the MvdHit.

reco/detectors/mvd/plugins/tasks/CbmMvdSensorHitfinderTask.cxx

@@ -403,6 +403,14 @@ void CbmMvdSensorHitfinderTask::ComputeCenterOfGravity(CbmMvdCluster* cluster, T
   LOG(debug) << "CbmMvdSensorHitfinderTask::X hit= " << fHitPosX << " Y hit= " << fHitPosY << " Z hit= " << fHitPosZ;
   LOG(debug) << "CbmMvdSensorHitfinderTask::-----------------------------------";
 
+  // Quick fix to get some errors for the MvdHits.
+  // Proposed value 8mum
+  // See Redmine issue 3066
+  // See plots with residuals from GitLab MR 1504
+  sigmaIn[0] = 0.0008;
+  sigmaIn[1] = 0.0008;
+  sigmaIn[2] = 0.;
+
   //   // Treat Sigma/Shift of the Cluster according to the Shape
   //   // This goes back to some results of a specific MIMOSA-26 beam time. Switch off for the time being.
   //