[Common] add dipole shift correction to muon QA task

Common/Tasks/qaMuon.cxx

@@ -223,6 +223,7 @@
     Configurable<double> fChamberResolutionX{"cfgChamberResolutionX", 0.4, "Chamber resolution along X configuration for refit"}; // 0.4cm pp, 0.2cm PbPb
     Configurable<double> fChamberResolutionY{"cfgChamberResolutionY", 0.4, "Chamber resolution along Y configuration for refit"}; // 0.4cm pp, 0.2cm PbPb
     Configurable<double> fSigmaCutImprove{"cfgSigmaCutImprove", 6., "Sigma cut for track improvement"};
+    Configurable<double> fDipoleZcorr{"cfgDipoleZcorr", 0.0f, "Correction to the dipole z position"};
   } configRealign;
 
   ///    Variables to event mixing criteria
@@ -512,7 +513,7 @@
         const auto& quadrant = quadrants[j];
         AxisSpec xAxis = {20, 0, 200, "|x| (cm)"};
         AxisSpec yAxis = {10, 0, 200, "|y| (cm)"};
         for (int chamber = 0; chamber < 10; chamber++) {
           std::string histPath = std::string("Alignment/same-event/Residuals/MFT/") + quadrant + "/CH" + std::to_string(chamber + 1) + "/";
           // Delta x at cluster
           residualsHistos[j][chamber]["dx_vs_x"] = registryResiduals.add((histPath + "dx_vs_x").c_str(), "Cluster x residual vs. x", {HistType::kTH2F, {xAxis, dxAxis}});
@@ -530,11 +531,11 @@
         }
       }
 
       for (size_t i = 0; i < 2; i++) {
         std::string topBottom = (i == 0) ? "top" : "bottom";
         AxisSpec deAxis = {26, 0, 26, "DE index"};
         AxisSpec phiAxisInner = {16, -180, 180, "#phi (degrees)"};
         for (size_t j = 0; j < 2; j++) {
           std::string sign = (j == 0) ? "positive" : "negative";
           for (int chamber = 0; chamber < 10; chamber++) {
             std::string histPath = std::string("Alignment/same-event/Residuals/MFT/MFT_") + topBottom + "/" + sign + "/CH" + std::to_string(chamber + 1) + "/";
@@ -1242,7 +1243,7 @@
     }
 
     if (!removeTrack) {
       for (auto& param : track) {
         param.setParameters(param.getSmoothParameters());
         param.setCovariances(param.getSmoothCovariances());
       }
@@ -1651,6 +1652,11 @@
       fgValues.errorClusters.emplace_back(eCls);
       fgValues.DEIDs.emplace_back(cluster.deId());
 
+      // subtract the dipole shift correction from the cluster z position
+      if (configRealign.fDipoleZcorr != 0) {
+        clusterMCH->z -= configRealign.fDipoleZcorr;
+      }
+
       // Add transformed cluster into temporary variable
       convertedTrack.createParamAtCluster(*clusterMCH);
     }
@@ -1663,6 +1669,12 @@
         LOGF(fatal, "Muon track %d has no associated clusters.", muon.globalIndex());
       }
 
+      // add back the dipole shift correction to the track z
+      if (configRealign.fDipoleZcorr != 0) {
+        auto& trackParam = *(convertedTrack.begin());
+        trackParam.setZ(trackParam.getZ() + configRealign.fDipoleZcorr);
+      }
+
       for (auto it = convertedTrack.begin(); it != convertedTrack.end(); it++) {
         std::vector<float> pos = {static_cast<float>(it->getNonBendingCoor()), static_cast<float>(it->getBendingCoor()), static_cast<float>(it->getZ())};
         fgValues.posClusters.emplace_back(pos);
@@ -2420,7 +2432,7 @@
       }
 
       // Loop over collisions
       for (auto& [collisionId, fgValuesColltmp] : collisions) {
 
         bool sameEvent = (fgValuesColltmp.bc == fgValuesColl.bc);
         bool mixedEvent = IsMixedEvent(fgValuesColltmp, fgValuesColl);
@@ -2468,7 +2480,7 @@
 
         int sign = (fgValuesMFTtmp.sign > 0) ? 1 : 2;
 
         for (auto& [collisionId, fgValuesColltmp] : collisions) {
 
           bool sameEvent = (fgValuesColltmp.bc == fgValuesColl.bc);
           bool mixedEvent = IsMixedEvent(fgValuesColltmp, fgValuesColl);
@@ -2506,7 +2518,7 @@
 
       // do collision loop and (again) propagation?
       // propagation in principle already done in runMuonQA?
       for (auto& [collisionId, fgValuesCollGlo] : collisions) {
 
         bool sameEvent = (fgValuesCollGlo.bc == fgValuesColl.bc);
         bool mixedEvent = IsMixedEvent(fgValuesCollGlo, fgValuesColl);
@@ -2556,7 +2568,7 @@
 
       // Do extrapolation for muons to all reference planes
       std::vector<VarTrack> mchTrackExtrap;
       for (const double z : zRefPlane) {
         VarTrack fgValues;
         if (configRealign.fDoRealign) {
           FillPropagation(mchrealigned, VarColl{}, fgValues, kToZ, z);
@@ -2592,7 +2604,7 @@
 
         // Do extrapolation for MFTs to all reference planes
         std::vector<VarTrack> mftTrackExtrap;
         for (const double z : zRefPlane) {
           VarTrack fgValues;
           FillPropagation<0, 1>(mft, fgValuesCollMFT, mchTrackExtrap[1], fgValues, kToZ, z);
           mftTrackExtrap.emplace_back(fgValues);
@@ -2758,7 +2770,7 @@
     }
 
     //// Second loop over global muon tracks
     for (auto& [mchIndex, globalMuonsVector] : matchingCandidates) {
 
       //// sort matching candidates in ascending order based on the matching chi2
       auto compareChi2 = [&muons](uint64_t trackIndex1, uint64_t trackIndex2) -> bool {