version from Alex with ExB correction, produces pt bias, not to be used

TRD/AliTRDrecoParam.cxx

@@ -156,7 +156,7 @@ AliTRDrecoParam::AliTRDrecoParam(const AliTRDrecoParam &ref)
   // tracklet params
   memcpy(fdzdxCorrFactor, ref.fdzdxCorrFactor, 2*sizeof(Double_t));
   memcpy(fdzdxCorrRCbias, ref.fdzdxCorrRCbias, 2*sizeof(Double_t));
-  memcpy(fYcorrTailCancel, ref.fdzdxCorrRCbias, 6*sizeof(Double_t));
+  memcpy(fYcorrTailCancel, ref.fdzdxCorrRCbias, 8*sizeof(Double_t));
   memcpy(fS2Ycorr, ref.fS2Ycorr, 2*sizeof(Double_t));
 }
 
@@ -215,7 +215,7 @@ AliTRDrecoParam& AliTRDrecoParam::operator=(const AliTRDrecoParam &ref)
   // tracklet params
   memcpy(fdzdxCorrFactor, ref.fdzdxCorrFactor, 2*sizeof(Double_t));
   memcpy(fdzdxCorrRCbias, ref.fdzdxCorrRCbias, 2*sizeof(Double_t));
-  memcpy(fYcorrTailCancel, ref.fdzdxCorrRCbias, 6*sizeof(Double_t));
+  memcpy(fYcorrTailCancel, ref.fdzdxCorrRCbias, 8*sizeof(Double_t));
   memcpy(fS2Ycorr, ref.fS2Ycorr, 2*sizeof(Double_t));
   return *this;
 }
@@ -355,9 +355,10 @@ void  AliTRDrecoParam::SetTrackletParams(Double_t *par)
     fYcorrTailCancel[0][0] = par[5]; fYcorrTailCancel[0][1] = par[6];  // opposite sign !RC
     fYcorrTailCancel[1][0] = par[7]; fYcorrTailCancel[1][1] = par[8];  // same sign !RC
     fYcorrTailCancel[2][0] = par[9]; fYcorrTailCancel[2][1] = par[10]; // RC
+    fYcorrTailCancel[3][0] = par[11];fYcorrTailCancel[3][1] = par[12]; // RC
     // inflation factor of error parameterization in r-phi due to wrong estimation of residuals. 
-    fS2Ycorr[0] = par[11];  // opposite sign, 
-    fS2Ycorr[1] = par[12];  // same sign
+    fS2Ycorr[0] = par[13];  // opposite sign, 
+    fS2Ycorr[1] = par[14];  // same sign
 
   } else {
     // correct dzdx for the bias in z
@@ -368,10 +369,11 @@ void  AliTRDrecoParam::SetTrackletParams(Double_t *par)
     fdzdxCorrRCbias[1] = -0.012; // dz/dx < 0
     /// correct x_cross for the bias in dzdx
     fdzdxXcrossFactor  = 0.14;
-    // y linear q/pt correction due to wrong tail cancellation. 
-    fYcorrTailCancel[0][0] = 0.;   fYcorrTailCancel[0][1] = 0.027;  // opposite sign !RC
-    fYcorrTailCancel[1][0] = 0.04; fYcorrTailCancel[1][1] = 0.027;  // same sign !RC
-    fYcorrTailCancel[2][0] = 0.013;fYcorrTailCancel[2][1] = 0.018;  // RC
+    // y linear tg(phi)-ExB correction due to wrong tail cancellation. 
+    fYcorrTailCancel[0][0] =-0.02; fYcorrTailCancel[0][1] = 0.13;   // opposite sign !RC
+    fYcorrTailCancel[1][0] = 0.01; fYcorrTailCancel[1][1] = 0.115;  // same sign !RC
+    fYcorrTailCancel[2][0] = 0.003;fYcorrTailCancel[2][1] = 0.075;  // opposite sign RC
+    fYcorrTailCancel[3][0] = 0.005;fYcorrTailCancel[3][1] = 0.1;    // same sign RC
     // inflation factor of error parameterization in r-phi due to wrong estimation of residuals. 
     fS2Ycorr[0] = 5.;  // opposite sign, 
     fS2Ycorr[1] = 10;  // same sign

TRD/AliTRDrecoParam.h

@@ -204,7 +204,7 @@ class AliTRDrecoParam : public AliDetectorRecoParam
   Double_t  fdzdxCorrFactor[2];      // correction of dzdx estimation due to z bias; [0] for !RC, [1] for RC
   Double_t  fdzdxCorrRCbias[2];      // correction of dzdx estimation bias for RC; [0] for dz/dx>0, [1] for dz/dx<0
   Double_t  fdzdxXcrossFactor;       // bias in dzdx of estimated xcross [RC]
-  Double_t  fYcorrTailCancel[3][2];  // y linear q/pt correction due to wrong tail cancellation. [0] opposite sign !RC, [1] same sign !RC, [2] RC
+  Double_t  fYcorrTailCancel[4][2];  // y linear dydx-ExB correction due to wrong tail cancellation. [0] opposite sign !RC, [1] same sign !RC, [2] opposite sign RC, [3] same sign RC
   Double_t  fS2Ycorr[2];             // inflation factor of error parameterization in r-phi due to wrong estimation of residuals. [0] opposite sign, [1] same sign
 
   // Clusterization parameter
@@ -220,7 +220,7 @@ class AliTRDrecoParam : public AliDetectorRecoParam
   Int_t     fNumberOfPresamples;     // number of presamples 
   Int_t     fNumberOfPostsamples;     // number of postsamples 
 
-  ClassDef(AliTRDrecoParam, 13)       // Reconstruction parameters for TRD detector
+  ClassDef(AliTRDrecoParam, 14)       // Reconstruction parameters for TRD detector
 
 };
 
@@ -276,7 +276,7 @@ inline void AliTRDrecoParam::SetTCParams(Double_t *par)
 //___________________________________________________
 inline void AliTRDrecoParam::GetYcorrTailCancel(Int_t it, Double_t par[2]) const
 {
-  if(it<0||it>2) return;
+  if(it<0||it>3) return;
   par[0] = fYcorrTailCancel[it][0]; par[1] = fYcorrTailCancel[it][1]; 
 }
 

TRD/AliTRDseedV1.cxx

@@ -662,7 +662,7 @@ void AliTRDseedV1::UnbiasDZDX(Bool_t rc)
 }
 
 //____________________________________________________________________
-Double_t AliTRDseedV1::UnbiasY(Bool_t rc, Bool_t sgn, Int_t chg)
+Double_t AliTRDseedV1::UnbiasY(Bool_t rc, Bool_t sgn)
 {
 // correct y coordinate for tail cancellation. This should be fixed by considering TC as a function of q/pt. 
 //  rc : TRUE if tracklet crosses rows
@@ -671,13 +671,14 @@ Double_t AliTRDseedV1::UnbiasY(Bool_t rc, Bool_t sgn, Int_t chg)
 
   const AliTRDrecoParam* const recoParam = fkReconstructor->GetRecoParam();
   if(!recoParam) return 0.;
+  Double_t dphi(fYref[1] - fExB);
   Double_t par[2]={0.};
-  if(rc) recoParam->GetYcorrTailCancel(2, par);
-  else{
-    if(sgn && 1./fPt > 1.5)  recoParam->GetYcorrTailCancel(1, par);
-    else if(!sgn)  recoParam->GetYcorrTailCancel(0, par);
-  }
-  return par[0]+par[1]*chg/fPt;
+  if(rc) recoParam->GetYcorrTailCancel(sgn?3:2, par);
+  else {
+    if(TMath::Abs(dphi)<0.2) return 0.;
+    recoParam->GetYcorrTailCancel(sgn?1:0, par);
+  }  
+  return par[0]+par[1]*dphi;  
 }
 
 
@@ -2161,7 +2162,7 @@ Bool_t AliTRDseedV1::Fit(UChar_t opt)
 
 
 //____________________________________________________________________
-Bool_t AliTRDseedV1::FitRobust(AliTRDpadPlane *pp, Bool_t sgn, Int_t chg, Int_t opt)
+Bool_t AliTRDseedV1::FitRobust(AliTRDpadPlane *pp, Bool_t sgn, Int_t opt)
 {
 //
 // Linear fit of the clusters attached to the tracklet
@@ -2215,7 +2216,7 @@ Bool_t AliTRDseedV1::FitRobust(AliTRDpadPlane *pp, Bool_t sgn, Int_t chg, Int_t
   Int_t n(0),          // clusters used in fit 
         row[]={-1, -1},// pad row spanned by the tracklet
         col(-1);       // pad column of current cluster
-  Double_t ycorr(UnbiasY(IsRowCross(), sgn, chg)),
+  Double_t ycorr(UnbiasY(IsRowCross(), sgn)),
            kS2Ycorr(recoParam->GetS2Ycorr(sgn));
 
   AliTRDcluster *c(NULL), **jc = &fClusters[0];

TRD/AliTRDseedV1.h

@@ -91,7 +91,7 @@ class AliTRDseedV1 : public AliTRDtrackletBase
   void      CookLabels();
   Bool_t    CookPID();
   Bool_t    Fit(UChar_t opt=0); // OBSOLETE
-  Bool_t    FitRobust(AliTRDpadPlane *pp, Bool_t sgn, Int_t chg, Int_t opt=0);
+  Bool_t    FitRobust(AliTRDpadPlane *pp, Bool_t sgn, Int_t opt=0);
   Double_t  EstimatedCrossPoint(AliTRDpadPlane *pp);
   Bool_t    Init(const AliTRDtrackV1 *track);
   void      Init(const AliRieman *fit);
@@ -217,7 +217,7 @@ class AliTRDseedV1 : public AliTRDtrackletBase
 protected:
   void      Copy(TObject &ref) const;
   void      UnbiasDZDX(Bool_t rc);
-  Double_t  UnbiasY(Bool_t rc, Bool_t sgn, Int_t chg);
+  Double_t  UnbiasY(Bool_t rc, Bool_t sgn);
 
 private:
   inline void SetN(Int_t n);

TRD/AliTRDtrackerV1.cxx

@@ -956,7 +956,7 @@ Int_t AliTRDtrackerV1::FollowBackProlongation(AliTRDtrackV1 &t)
     // tilt correction options
     // 0 : no correction
     // 2 : pseudo tilt correction
-    if(!ptrTracklet->FitRobust(fGeom->GetPadPlane(ily, stk), prod>0., t.Charge())){
+    if(!ptrTracklet->FitRobust(fGeom->GetPadPlane(ily, stk), prod>0.)){
       t.SetErrStat(AliTRDtrackV1::kNoFit, ily);
       AliDebug(4, "Failed Tracklet Fit");
       continue;