}
//__________________________________________________________________________
-void AliMUONTrackExtrap::LinearExtrapToZ(AliMUONTrackParam* trackParam, Double_t zEnd, Bool_t updatePropagator)
+void AliMUONTrackExtrap::LinearExtrapToZ(AliMUONTrackParam* trackParam, Double_t zEnd)
{
- /// Track parameters (and their covariances if any) linearly extrapolated to the plane at "zEnd".
+ /// Track parameters linearly extrapolated to the plane at "zEnd".
/// On return, results from the extrapolation are updated in trackParam.
if (trackParam->GetZ() == zEnd) return; // nothing to be done if same z
trackParam->SetNonBendingCoor(trackParam->GetNonBendingCoor() + trackParam->GetNonBendingSlope() * dZ);
trackParam->SetBendingCoor(trackParam->GetBendingCoor() + trackParam->GetBendingSlope() * dZ);
trackParam->SetZ(zEnd);
+}
+
+//__________________________________________________________________________
+void AliMUONTrackExtrap::LinearExtrapToZCov(AliMUONTrackParam* trackParam, Double_t zEnd, Bool_t updatePropagator)
+{
+ /// Track parameters and their covariances linearly extrapolated to the plane at "zEnd".
+ /// On return, results from the extrapolation are updated in trackParam.
- // Update track parameters covariances if any
- if (trackParam->CovariancesExist()) {
- TMatrixD paramCov(trackParam->GetCovariances());
- paramCov(0,0) += dZ * dZ * paramCov(1,1) + 2. * dZ * paramCov(0,1);
- paramCov(0,1) += dZ * paramCov(1,1);
- paramCov(1,0) = paramCov(0,1);
- paramCov(2,2) += dZ * dZ * paramCov(3,3) + 2. * dZ * paramCov(2,3);
- paramCov(2,3) += dZ * paramCov(3,3);
- paramCov(3,2) = paramCov(2,3);
- trackParam->SetCovariances(paramCov);
-
- // Update the propagator if required
- if (updatePropagator) {
- TMatrixD jacob(5,5);
- jacob.UnitMatrix();
- jacob(0,1) = dZ;
- jacob(2,3) = dZ;
- trackParam->UpdatePropagator(jacob);
- }
-
+ if (trackParam->GetZ() == zEnd) return; // nothing to be done if same z
+
+ // No need to propagate the covariance matrix if it does not exist
+ if (!trackParam->CovariancesExist()) {
+ cout<<"W-AliMUONTrackExtrap::LinearExtrapToZCov: Covariance matrix does not exist"<<endl;
+ // Extrapolate linearly track parameters to "zEnd"
+ LinearExtrapToZ(trackParam,zEnd);
+ return;
}
+ // Compute track parameters
+ Double_t dZ = zEnd - trackParam->GetZ();
+ trackParam->SetNonBendingCoor(trackParam->GetNonBendingCoor() + trackParam->GetNonBendingSlope() * dZ);
+ trackParam->SetBendingCoor(trackParam->GetBendingCoor() + trackParam->GetBendingSlope() * dZ);
+ trackParam->SetZ(zEnd);
+
+ // Calculate the jacobian related to the track parameters linear extrapolation to "zEnd"
+ TMatrixD jacob(5,5);
+ jacob.UnitMatrix();
+ jacob(0,1) = dZ;
+ jacob(2,3) = dZ;
+
+ // Extrapolate track parameter covariances to "zEnd"
+ TMatrixD tmp(trackParam->GetCovariances(),TMatrixD::kMultTranspose,jacob);
+ TMatrixD tmp2(jacob,TMatrixD::kMult,tmp);
+ trackParam->SetCovariances(tmp2);
+
+ // Update the propagator if required
+ if (updatePropagator) trackParam->UpdatePropagator(jacob);
}
//__________________________________________________________________________
-void AliMUONTrackExtrap::ExtrapToZ(AliMUONTrackParam* trackParam, Double_t zEnd)
+Bool_t AliMUONTrackExtrap::ExtrapToZ(AliMUONTrackParam* trackParam, Double_t zEnd)
{
/// Interface to track parameter extrapolation to the plane at "Z" using Helix or Rungekutta algorithm.
/// On return, the track parameters resulting from the extrapolation are updated in trackParam.
- if (!fgFieldON) AliMUONTrackExtrap::LinearExtrapToZ(trackParam,zEnd);
- else if (fgkUseHelix) AliMUONTrackExtrap::ExtrapToZHelix(trackParam,zEnd);
- else AliMUONTrackExtrap::ExtrapToZRungekutta(trackParam,zEnd);
+ if (!fgFieldON) {
+ AliMUONTrackExtrap::LinearExtrapToZ(trackParam,zEnd);
+ return kTRUE;
+ }
+ else if (fgkUseHelix) return AliMUONTrackExtrap::ExtrapToZHelix(trackParam,zEnd);
+ else return AliMUONTrackExtrap::ExtrapToZRungekutta(trackParam,zEnd);
}
//__________________________________________________________________________
-void AliMUONTrackExtrap::ExtrapToZHelix(AliMUONTrackParam* trackParam, Double_t zEnd)
+Bool_t AliMUONTrackExtrap::ExtrapToZHelix(AliMUONTrackParam* trackParam, Double_t zEnd)
{
/// Track parameter extrapolation to the plane at "Z" using Helix algorithm.
/// On return, the track parameters resulting from the extrapolation are updated in trackParam.
- if (trackParam->GetZ() == zEnd) return; // nothing to be done if same Z
+ if (trackParam->GetZ() == zEnd) return kTRUE; // nothing to be done if same Z
Double_t forwardBackward; // +1 if forward, -1 if backward
if (zEnd < trackParam->GetZ()) forwardBackward = 1.0; // spectro. z<0
else forwardBackward = -1.0;
}
// Recover track parameters (charge back for forward motion)
RecoverTrackParam(v3, chargeExtrap * forwardBackward, trackParam);
+ return kTRUE;
}
//__________________________________________________________________________
-void AliMUONTrackExtrap::ExtrapToZRungekutta(AliMUONTrackParam* trackParam, Double_t zEnd)
+Bool_t AliMUONTrackExtrap::ExtrapToZRungekutta(AliMUONTrackParam* trackParam, Double_t zEnd)
{
/// Track parameter extrapolation to the plane at "Z" using Rungekutta algorithm.
/// On return, the track parameters resulting from the extrapolation are updated in trackParam.
- if (trackParam->GetZ() == zEnd) return; // nothing to be done if same Z
+ if (trackParam->GetZ() == zEnd) return kTRUE; // nothing to be done if same Z
Double_t forwardBackward; // +1 if forward, -1 if backward
if (zEnd < trackParam->GetZ()) forwardBackward = 1.0; // spectro. z<0
else forwardBackward = -1.0;
Double_t dZ, step;
Int_t stepNumber = 0;
- // Extrapolation loop (until within tolerance)
+ // Extrapolation loop (until within tolerance or the track turn around)
Double_t residue = zEnd - trackParam->GetZ();
+ Bool_t uturn = kFALSE;
+ Bool_t tooManyStep = kFALSE;
while (TMath::Abs(residue) > fgkRungeKuttaMaxResidue && stepNumber <= fgkMaxStepNumber) {
+
dZ = zEnd - trackParam->GetZ();
// step lenght assuming linear trajectory
step = dZ * TMath::Sqrt(1.0 + trackParam->GetBendingSlope()*trackParam->GetBendingSlope() +
trackParam->GetNonBendingSlope()*trackParam->GetNonBendingSlope());
ConvertTrackParamForExtrap(trackParam, forwardBackward, v3);
+
do { // reduce step lenght while zEnd oversteped
if (stepNumber > fgkMaxStepNumber) {
cout<<"W-AliMUONTrackExtrap::ExtrapToZRungekutta: Too many trials: "<<stepNumber<<endl;
+ tooManyStep = kTRUE;
break;
}
stepNumber ++;
residue = zEnd - v3New[2];
step *= dZ/(v3New[2]-trackParam->GetZ());
} while (residue*dZ < 0 && TMath::Abs(residue) > fgkRungeKuttaMaxResidue);
- RecoverTrackParam(v3New, chargeExtrap * forwardBackward, trackParam);
+
+ if (v3New[5]*v3[5] < 0) { // the track turned around
+ cout<<"W-AliMUONTrackExtrap::ExtrapToZRungekutta: The track turned around"<<endl;
+ uturn = kTRUE;
+ break;
+ } else RecoverTrackParam(v3New, chargeExtrap * forwardBackward, trackParam);
+
}
// terminate the extropolation with a straight line up to the exact "zEnd" value
- trackParam->SetNonBendingCoor(trackParam->GetNonBendingCoor() + residue * trackParam->GetNonBendingSlope());
- trackParam->SetBendingCoor(trackParam->GetBendingCoor() + residue * trackParam->GetBendingSlope());
- trackParam->SetZ(zEnd);
+ if (uturn) {
+
+ // track ends +-100 meters away in the bending direction
+ dZ = zEnd - v3[2];
+ Double_t bendingSlope = TMath::Sign(1.e4,-fgSimpleBValue*trackParam->GetInverseBendingMomentum()) / dZ;
+ Double_t pZ = TMath::Abs(1. / trackParam->GetInverseBendingMomentum()) / TMath::Sqrt(1.0 + bendingSlope * bendingSlope);
+ Double_t nonBendingSlope = TMath::Sign(TMath::Abs(v3[3]) * v3[6] / pZ, trackParam->GetNonBendingSlope());
+ trackParam->SetNonBendingCoor(trackParam->GetNonBendingCoor() + dZ * nonBendingSlope);
+ trackParam->SetNonBendingSlope(nonBendingSlope);
+ trackParam->SetBendingCoor(trackParam->GetBendingCoor() + dZ * bendingSlope);
+ trackParam->SetBendingSlope(bendingSlope);
+ trackParam->SetZ(zEnd);
+
+ return kFALSE;
+
+ } else {
+
+ // track extrapolated normally
+ trackParam->SetNonBendingCoor(trackParam->GetNonBendingCoor() + residue * trackParam->GetNonBendingSlope());
+ trackParam->SetBendingCoor(trackParam->GetBendingCoor() + residue * trackParam->GetBendingSlope());
+ trackParam->SetZ(zEnd);
+
+ return !tooManyStep;
+
+ }
+
}
//__________________________________________________________________________
}
//__________________________________________________________________________
-void AliMUONTrackExtrap::ExtrapToZCov(AliMUONTrackParam* trackParam, Double_t zEnd, Bool_t updatePropagator)
+Bool_t AliMUONTrackExtrap::ExtrapToZCov(AliMUONTrackParam* trackParam, Double_t zEnd, Bool_t updatePropagator)
{
/// Track parameters and their covariances extrapolated to the plane at "zEnd".
/// On return, results from the extrapolation are updated in trackParam.
- if (trackParam->GetZ() == zEnd) return; // nothing to be done if same z
+ if (trackParam->GetZ() == zEnd) return kTRUE; // nothing to be done if same z
if (!fgFieldON) { // linear extrapolation if no magnetic field
- AliMUONTrackExtrap::LinearExtrapToZ(trackParam,zEnd,updatePropagator);
- return;
+ AliMUONTrackExtrap::LinearExtrapToZCov(trackParam,zEnd,updatePropagator);
+ return kTRUE;
}
// No need to propagate the covariance matrix if it does not exist
if (!trackParam->CovariancesExist()) {
cout<<"W-AliMUONTrackExtrap::ExtrapToZCov: Covariance matrix does not exist"<<endl;
// Extrapolate track parameters to "zEnd"
- ExtrapToZ(trackParam,zEnd);
- return;
+ return ExtrapToZ(trackParam,zEnd);
}
// Save the actual track parameters
const TMatrixD& kParamCov = trackParam->GetCovariances();
// Extrapolate track parameters to "zEnd"
- ExtrapToZ(trackParam,zEnd);
+ // Do not update the covariance matrix if the extrapolation failed
+ if (!ExtrapToZ(trackParam,zEnd)) return kFALSE;
// Get reference to the extrapolated parameters
const TMatrixD& extrapParam = trackParam->GetParameters();
// Calculate the jacobian related to the track parameters extrapolation to "zEnd"
+ Bool_t extrapStatus = kTRUE;
TMatrixD jacob(5,5);
jacob.Zero();
TMatrixD dParam(5,1);
trackParamSave.SetZ(zBegin);
// Extrapolate new track parameters to "zEnd"
- ExtrapToZ(&trackParamSave,zEnd);
+ if (!ExtrapToZ(&trackParamSave,zEnd)) {
+ cout<<"W-AliMUONTrackExtrap::ExtrapToZCov: Bad covariance matrix"<<endl;
+ extrapStatus = kFALSE;
+ }
// Calculate the jacobian
TMatrixD jacobji(trackParamSave.GetParameters(),TMatrixD::kMinus,extrapParam);
// Update the propagator if required
if (updatePropagator) trackParam->UpdatePropagator(jacob);
+
+ return extrapStatus;
}
//__________________________________________________________________________
-void AliMUONTrackExtrap::AddMCSEffectInAbsorber(AliMUONTrackParam* param, Double_t pathLength, Double_t f0, Double_t f1, Double_t f2)
+void AliMUONTrackExtrap::AddMCSEffectInAbsorber(AliMUONTrackParam* param, Double_t signedPathLength, Double_t f0, Double_t f1, Double_t f2)
{
/// Add to the track parameter covariances the effects of multiple Coulomb scattering
- /// The absorber correction parameters are supposed to be calculated at the current track z-position
+ /// signedPathLength must have the sign of (zOut - zIn) where all other parameters are assumed to be given at zOut.
// absorber related covariance parameters
Double_t bendingSlope = param->GetBendingSlope();
Double_t inverseBendingMomentum = param->GetInverseBendingMomentum();
Double_t alpha2 = 0.0136 * 0.0136 * inverseBendingMomentum * inverseBendingMomentum * (1.0 + bendingSlope * bendingSlope) /
(1.0 + bendingSlope *bendingSlope + nonBendingSlope * nonBendingSlope); // velocity = 1
+ Double_t pathLength = TMath::Abs(signedPathLength);
Double_t varCoor = alpha2 * (pathLength * pathLength * f0 - 2. * pathLength * f1 + f2);
- Double_t covCorrSlope = alpha2 * (pathLength * f0 - f1);
+ Double_t covCorrSlope = TMath::Sign(1.,signedPathLength) * alpha2 * (pathLength * f0 - f1);
Double_t varSlop = alpha2 * f0;
- // compute derivative d(q/Pxy) / dSlopeX and d(q/Pxy) / dSlopeX
- Double_t dqPxydSlopeX = inverseBendingMomentum * nonBendingSlope / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
- Double_t dqPxydSlopeY = - inverseBendingMomentum * nonBendingSlope*nonBendingSlope * bendingSlope /
- (1. + bendingSlope*bendingSlope) / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
-
// Set MCS covariance matrix
TMatrixD newParamCov(param->GetCovariances());
// Non bending plane
// Bending plane
newParamCov(2,2) += varCoor; newParamCov(2,3) += covCorrSlope;
newParamCov(3,2) += covCorrSlope; newParamCov(3,3) += varSlop;
- // Inverse bending momentum (due to dependences with bending and non bending slopes)
- newParamCov(4,0) += dqPxydSlopeX * covCorrSlope; newParamCov(0,4) += dqPxydSlopeX * covCorrSlope;
- newParamCov(4,1) += dqPxydSlopeX * varSlop; newParamCov(1,4) += dqPxydSlopeX * varSlop;
- newParamCov(4,2) += dqPxydSlopeY * covCorrSlope; newParamCov(2,4) += dqPxydSlopeY * covCorrSlope;
- newParamCov(4,3) += dqPxydSlopeY * varSlop; newParamCov(3,4) += dqPxydSlopeY * varSlop;
- newParamCov(4,4) += (dqPxydSlopeX*dqPxydSlopeX + dqPxydSlopeY*dqPxydSlopeY) * varSlop;
+
+ // Set momentum related covariances if B!=0
+ if (fgFieldON) {
+ // compute derivative d(q/Pxy) / dSlopeX and d(q/Pxy) / dSlopeY
+ Double_t dqPxydSlopeX = inverseBendingMomentum * nonBendingSlope / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
+ Double_t dqPxydSlopeY = - inverseBendingMomentum * nonBendingSlope*nonBendingSlope * bendingSlope /
+ (1. + bendingSlope*bendingSlope) / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
+ // Inverse bending momentum (due to dependences with bending and non bending slopes)
+ newParamCov(4,0) += dqPxydSlopeX * covCorrSlope; newParamCov(0,4) += dqPxydSlopeX * covCorrSlope;
+ newParamCov(4,1) += dqPxydSlopeX * varSlop; newParamCov(1,4) += dqPxydSlopeX * varSlop;
+ newParamCov(4,2) += dqPxydSlopeY * covCorrSlope; newParamCov(2,4) += dqPxydSlopeY * covCorrSlope;
+ newParamCov(4,3) += dqPxydSlopeY * varSlop; newParamCov(3,4) += dqPxydSlopeY * varSlop;
+ newParamCov(4,4) += (dqPxydSlopeX*dqPxydSlopeX + dqPxydSlopeY*dqPxydSlopeY) * varSlop;
+ }
// Set new covariances
param->SetCovariances(newParamCov);
// Position of the Branson plane (spectro. (z<0))
Double_t zB = (f1>0.) ? absZBeg - f2/f1 : 0.;
- // Add MCS effects to current parameter covariances
- AddMCSEffectInAbsorber(param, pathLength, f0, f1, f2);
+ // Add MCS effects to current parameter covariances (spectro. (z<0))
+ AddMCSEffectInAbsorber(param, -pathLength, f0, f1, f2);
// Get track parameters and covariances in the Branson plane corrected for magnetic field effect
ExtrapToZCov(param,zVtx);
- LinearExtrapToZ(param,zB);
+ LinearExtrapToZCov(param,zB);
// compute track parameters at vertex
TMatrixD newParam(5,1);
Double_t x0 = 0.; // radiation-length (cm-1)
Double_t atomicA = 0.; // A of material
Double_t atomicZ = 0.; // Z of material
+ Double_t atomicZoverA = 0.; // Z/A of material
Double_t localPathLength = 0;
Double_t remainingPathLength = pathLength;
Double_t zB = trackXYZIn[2];
TGeoMaterial *material = currentnode->GetVolume()->GetMedium()->GetMaterial();
rho = material->GetDensity();
x0 = material->GetRadLen();
- if (!material->IsMixture()) x0 /= rho; // different normalization in the modeler for mixture
atomicA = material->GetA();
atomicZ = material->GetZ();
+ if(material->IsMixture()){
+ TGeoMixture * mixture = (TGeoMixture*)material;
+ atomicZoverA = 0.;
+ Double_t sum = 0.;
+ for (Int_t iel=0;iel<mixture->GetNelements();iel++){
+ sum += mixture->GetWmixt()[iel];
+ atomicZoverA += mixture->GetZmixt()[iel]*mixture->GetWmixt()[iel]/mixture->GetAmixt()[iel];
+ }
+ atomicZoverA/=sum;
+ }
+ else atomicZoverA = atomicZ/atomicA;
// Get path length within this material
gGeoManager->FindNextBoundary(remainingPathLength);
f1 += (dzE*dzE - dzB*dzB) / b[2] / b[2] / x0 / 2.;
f2 += (dzE*dzE*dzE - dzB*dzB*dzB) / b[2] / b[2] / b[2] / x0 / 3.;
meanRho += localPathLength * rho;
- totalELoss += BetheBloch(pTotal, localPathLength, rho, atomicA, atomicZ);
- sigmaELoss2 += EnergyLossFluctuation2(pTotal, localPathLength, rho, atomicA, atomicZ);
+ totalELoss += BetheBloch(pTotal, localPathLength, rho, atomicZ, atomicZoverA);
+ sigmaELoss2 += EnergyLossFluctuation2(pTotal, localPathLength, rho, atomicZoverA);
// prepare next step
zB = zE;
void AliMUONTrackExtrap::AddMCSEffect(AliMUONTrackParam *param, Double_t dZ, Double_t x0)
{
/// Add to the track parameter covariances the effects of multiple Coulomb scattering
- /// through a material of thickness "dZ" and of radiation length "x0"
+ /// through a material of thickness "Abs(dZ)" and of radiation length "x0"
/// assuming linear propagation and using the small angle approximation.
+ /// dZ = zOut - zIn (sign is important) and "param" is assumed to be given zOut.
+ /// If x0 <= 0., assume dZ = pathLength/x0 and consider the material thickness as negligible.
Double_t bendingSlope = param->GetBendingSlope();
Double_t nonBendingSlope = param->GetNonBendingSlope();
(1.0 + bendingSlope * bendingSlope) /
(1.0 + bendingSlope *bendingSlope + nonBendingSlope * nonBendingSlope);
// Path length in the material
- Double_t pathLength = TMath::Abs(dZ) * TMath::Sqrt(1.0 + bendingSlope*bendingSlope + nonBendingSlope*nonBendingSlope);
- Double_t pathLength2 = pathLength * pathLength;
+ Double_t signedPathLength = dZ * TMath::Sqrt(1.0 + bendingSlope*bendingSlope + nonBendingSlope*nonBendingSlope);
+ Double_t pathLengthOverX0 = (x0 > 0.) ? TMath::Abs(signedPathLength) / x0 : TMath::Abs(signedPathLength);
// relativistic velocity
Double_t velo = 1.;
// Angular dispersion square of the track (variance) in a plane perpendicular to the trajectory
- Double_t theta02 = 0.0136 / velo * (1 + 0.038 * TMath::Log(pathLength/x0));
- theta02 *= theta02 * inverseTotalMomentum2 * pathLength / x0;
+ Double_t theta02 = 0.0136 / velo * (1 + 0.038 * TMath::Log(pathLengthOverX0));
+ theta02 *= theta02 * inverseTotalMomentum2 * pathLengthOverX0;
- Double_t varCoor = pathLength2 * theta02 / 3.;
+ Double_t varCoor = (x0 > 0.) ? signedPathLength * signedPathLength * theta02 / 3. : 0.;
Double_t varSlop = theta02;
- Double_t covCorrSlope = pathLength * theta02 / 2.;
-
- // compute derivative d(q/Pxy) / dSlopeX and d(q/Pxy) / dSlopeY
- Double_t dqPxydSlopeX = inverseBendingMomentum * nonBendingSlope / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
- Double_t dqPxydSlopeY = - inverseBendingMomentum * nonBendingSlope*nonBendingSlope * bendingSlope /
- (1. + bendingSlope*bendingSlope) / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
+ Double_t covCorrSlope = (x0 > 0.) ? signedPathLength * theta02 / 2. : 0.;
// Set MCS covariance matrix
TMatrixD newParamCov(param->GetCovariances());
// Bending plane
newParamCov(2,2) += varCoor; newParamCov(2,3) += covCorrSlope;
newParamCov(3,2) += covCorrSlope; newParamCov(3,3) += varSlop;
- // Inverse bending momentum (due to dependences with bending and non bending slopes)
- newParamCov(4,0) += dqPxydSlopeX * covCorrSlope; newParamCov(0,4) += dqPxydSlopeX * covCorrSlope;
- newParamCov(4,1) += dqPxydSlopeX * varSlop; newParamCov(1,4) += dqPxydSlopeX * varSlop;
- newParamCov(4,2) += dqPxydSlopeY * covCorrSlope; newParamCov(2,4) += dqPxydSlopeY * covCorrSlope;
- newParamCov(4,3) += dqPxydSlopeY * varSlop; newParamCov(3,4) += dqPxydSlopeY * varSlop;
- newParamCov(4,4) += (dqPxydSlopeX*dqPxydSlopeX + dqPxydSlopeY*dqPxydSlopeY) * varSlop;
+
+ // Set momentum related covariances if B!=0
+ if (fgFieldON) {
+ // compute derivative d(q/Pxy) / dSlopeX and d(q/Pxy) / dSlopeY
+ Double_t dqPxydSlopeX = inverseBendingMomentum * nonBendingSlope / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
+ Double_t dqPxydSlopeY = - inverseBendingMomentum * nonBendingSlope*nonBendingSlope * bendingSlope /
+ (1. + bendingSlope*bendingSlope) / (1. + nonBendingSlope*nonBendingSlope + bendingSlope*bendingSlope);
+ // Inverse bending momentum (due to dependences with bending and non bending slopes)
+ newParamCov(4,0) += dqPxydSlopeX * covCorrSlope; newParamCov(0,4) += dqPxydSlopeX * covCorrSlope;
+ newParamCov(4,1) += dqPxydSlopeX * varSlop; newParamCov(1,4) += dqPxydSlopeX * varSlop;
+ newParamCov(4,2) += dqPxydSlopeY * covCorrSlope; newParamCov(2,4) += dqPxydSlopeY * covCorrSlope;
+ newParamCov(4,3) += dqPxydSlopeY * varSlop; newParamCov(3,4) += dqPxydSlopeY * varSlop;
+ newParamCov(4,4) += (dqPxydSlopeX*dqPxydSlopeX + dqPxydSlopeY*dqPxydSlopeY) * varSlop;
+ }
// Set new covariances
param->SetCovariances(newParamCov);
// Correct for energy loss add multiple scattering dispersion in covariance matrix
CorrectELossEffectInAbsorber(trackParam, 0.5*totalELoss, 0.5*sigmaELoss2);
- AddMCSEffectInAbsorber(trackParam, pathLength, f0, f1, f2);
+ AddMCSEffectInAbsorber(trackParam, -pathLength, f0, f1, f2); // (spectro. (z<0))
ExtrapToZCov(trackParam, trackXYZIn[2]);
CorrectELossEffectInAbsorber(trackParam, 0.5*totalELoss, 0.5*sigmaELoss2);
ExtrapToZCov(trackParam, zVtx);
} else {
// add multiple scattering dispersion in covariance matrix
- AddMCSEffectInAbsorber(trackParam, pathLength, f0, f1, f2);
+ AddMCSEffectInAbsorber(trackParam, -pathLength, f0, f1, f2); // (spectro. (z<0))
ExtrapToZCov(trackParam, zVtx);
}
}
//__________________________________________________________________________
-Double_t AliMUONTrackExtrap::BetheBloch(Double_t pTotal, Double_t pathLength, Double_t rho, Double_t atomicA, Double_t atomicZ)
+Double_t AliMUONTrackExtrap::BetheBloch(Double_t pTotal, Double_t pathLength, Double_t rho, Double_t atomicZ, Double_t atomicZoverA)
{
/// Returns the mean total momentum energy loss of muon with total momentum='pTotal'
/// in the absorber layer of lenght='pathLength', density='rho', A='atomicA' and Z='atomicZ'
if (atomicZ < 13) i = (12. * atomicZ + 7.) * 1.e-9;
else i = (9.76 * atomicZ + 58.8 * TMath::Power(atomicZ,-0.19)) * 1.e-9;
- return pathLength * rho * AliExternalTrackParam::BetheBlochGeant(pTotal/muMass, rho, 0.20, 3.00, i, atomicZ/atomicA);
+ return pathLength * rho * AliExternalTrackParam::BetheBlochGeant(pTotal/muMass, rho, 0.20, 3.00, i, atomicZoverA);
}
//__________________________________________________________________________
-Double_t AliMUONTrackExtrap::EnergyLossFluctuation2(Double_t pTotal, Double_t pathLength, Double_t rho, Double_t atomicA, Double_t atomicZ)
+Double_t AliMUONTrackExtrap::EnergyLossFluctuation2(Double_t pTotal, Double_t pathLength, Double_t rho, Double_t atomicZoverA)
{
/// Returns the total momentum energy loss fluctuation of muon with total momentum='pTotal'
/// in the absorber layer of lenght='pathLength', density='rho', A='atomicA' and Z='atomicZ'
Double_t p2=pTotal*pTotal;
Double_t beta2=p2/(p2 + muMass*muMass);
- Double_t fwhm = 2. * k * rho * pathLength * atomicZ / atomicA / beta2; // FWHM of the energy loss Landau distribution
+ Double_t fwhm = 2. * k * rho * pathLength * atomicZoverA / beta2; // FWHM of the energy loss Landau distribution
Double_t sigma2 = fwhm * fwhm / (8.*log(2.)); // gaussian: fwmh = 2 * srqt(2*ln(2)) * sigma (i.e. fwmh = 2.35 * sigma)
//sigma2 = k * rho * pathLength * atomicZ / atomicA * eMass; // sigma2 of the energy loss gaussian distribution
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff