ClassImp(AliExternalTrackParam)
Double32_t AliExternalTrackParam::fgMostProbablePt=kMostProbablePt;
-
+Bool_t AliExternalTrackParam::fgUseLogTermMS = kFALSE;;
//_____________________________________________________________________________
AliExternalTrackParam::AliExternalTrackParam() :
AliVTrack(),
// azimuthal angle of the centre of the TPC sector in which the point
// xyz lies
//
+ const double kSafe = 1e-5;
Double_t radPos2 = xyz[0]*xyz[0]+xyz[1]*xyz[1];
Double_t radMax = 45.; // approximately ITS outer radius
- if (radPos2 < radMax*radMax) { // inside the ITS
-
+ if (radPos2 < radMax*radMax) { // inside the ITS
fAlpha = TMath::ATan2(pxpypz[1],pxpypz[0]);
} else { // outside the ITS
Float_t phiPos = TMath::Pi()+TMath::ATan2(-xyz[1], -xyz[0]);
fAlpha =
TMath::DegToRad()*(20*((((Int_t)(phiPos*TMath::RadToDeg()))/20))+10);
}
-
+ //
+ Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha);
+ // protection: avoid alpha being too close to 0 or +-pi/2
+ if (TMath::Abs(sn)<kSafe) {
+ fAlpha = kSafe;
+ cs=TMath::Cos(fAlpha);
+ sn=TMath::Sin(fAlpha);
+ }
+ else if (cs<kSafe) {
+ fAlpha -= TMath::Sign(kSafe, fAlpha);
+ cs=TMath::Cos(fAlpha);
+ sn=TMath::Sin(fAlpha);
+ }
// Get the vertex of origin and the momentum
TVector3 ver(xyz[0],xyz[1],xyz[2]);
TVector3 mom(pxpypz[0],pxpypz[1],pxpypz[2]);
+ //
+ // avoid momenta along axis
+ if (TMath::Abs(mom[0])<kSafe) mom[0] = TMath::Sign(kSafe*TMath::Abs(mom[1]), mom[0]);
+ if (TMath::Abs(mom[1])<kSafe) mom[1] = TMath::Sign(kSafe*TMath::Abs(mom[0]), mom[1]);
// Rotate to the local coordinate system
ver.RotateZ(-fAlpha);
// Covariance matrix (formulas to be simplified)
+ if (TMath::Abs( 1-fP[2]) < kSafe) fP[2] = 1.- kSafe; //Protection
+ else if (TMath::Abs(-1-fP[2]) < kSafe) fP[2] =-1.+ kSafe; //Protection
+
Double_t pt=1./TMath::Abs(fP[4]);
- Double_t cs=TMath::Cos(fAlpha), sn=TMath::Sin(fAlpha);
Double_t r=TMath::Sqrt((1.-fP[2])*(1.+fP[2]));
Double_t m00=-sn;// m10=cs;
//------------------------------------------------------------------
// This function corrects the track parameters for the crossed material.
// "xOverX0" - X/X0, the thickness in units of the radiation length.
- // "xTimesRho" - is the product length*density (g/cm^2).
+ // "xTimesRho" - is the product length*density (g/cm^2).
+ // It should be passed as negative when propagating tracks
+ // from the intreaction point to the outside of the central barrel.
// "mass" - the mass of this particle (GeV/c^2).
// "dEdx" - mean enery loss (GeV/(g/cm^2)
// "anglecorr" - switch for the angular correction
Double_t cC43 = 0.;
Double_t cC44 = 0.;
if (xOverX0 != 0) {
- Double_t theta2=14.1*14.1/(beta2*p2*1e6)*TMath::Abs(xOverX0);
- //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33;
- if(theta2>TMath::Pi()*TMath::Pi()) return kFALSE;
- cC22 = theta2*((1.-fP2)*(1.+fP2))*(1. + fP3*fP3);
- cC33 = theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
- cC43 = theta2*fP3*fP4*(1. + fP3*fP3);
- cC44 = theta2*fP3*fP4*fP3*fP4;
+ //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*TMath::Abs(d)*9.36*2.33;
+ Double_t theta2=0.0136*0.0136/(beta2*p2)*TMath::Abs(xOverX0);
+ if (GetUseLogTermMS()) {
+ double lt = 1+0.038*TMath::Log(TMath::Abs(xOverX0));
+ if (lt>0) theta2 *= lt*lt;
+ }
+ if(theta2>TMath::Pi()*TMath::Pi()) return kFALSE;
+ cC22 = theta2*((1.-fP2)*(1.+fP2))*(1. + fP3*fP3);
+ cC33 = theta2*(1. + fP3*fP3)*(1. + fP3*fP3);
+ cC43 = theta2*fP3*fP4*(1. + fP3*fP3);
+ cC44 = theta2*fP3*fP4*fP3*fP4;
}
//Calculating the energy loss corrections************************
// This function corrects the track parameters for the crossed material.
// "xOverX0" - X/X0, the thickness in units of the radiation length.
// "xTimesRho" - is the product length*density (g/cm^2).
+ // It should be passed as negative when propagating tracks
+ // from the intreaction point to the outside of the central barrel.
// "mass" - the mass of this particle (GeV/c^2).
// "anglecorr" - switch for the angular correction
// "Bethe" - function calculating the energy loss (GeV/(g/cm^2))
// using the full Geant-like Bethe-Bloch formula parameterization
// "xOverX0" - X/X0, the thickness in units of the radiation length.
// "xTimesRho" - is the product length*density (g/cm^2).
+ // It should be passed as negative when propagating tracks
+ // from the intreaction point to the outside of the central barrel.
// "mass" - the mass of this particle (GeV/c^2).
// "density" - mean density (g/cm^3)
// "zOverA" - mean Z/A
//
// This function corrects the track parameters for the crossed material
// "d" - the thickness (fraction of the radiation length)
+ // It should be passed as negative when propagating tracks
+ // from the intreaction point to the outside of the central barrel.
// "x0" - the radiation length (g/cm^2)
// "mass" - the mass of this particle (GeV/c^2)
//------------------------------------------------------------------
Double_t f1=fP[2], f2=f1 + x2r;
if (TMath::Abs(f1) >= kAlmost1) return kFALSE;
if (TMath::Abs(f2) >= kAlmost1) return kFALSE;
+ if (TMath::Abs(fP[4])< kAlmost0) return kFALSE;
Double_t &fP0=fP[0], &fP1=fP[1], &fP2=fP[2], &fP3=fP[3], &fP4=fP[4];
Double_t
&fC40=fC[10], &fC41=fC[11], &fC42=fC[12], &fC43=fC[13], &fC44=fC[14];
Double_t r1=TMath::Sqrt((1.-f1)*(1.+f1)), r2=TMath::Sqrt((1.-f2)*(1.+f2));
+ if (TMath::Abs(r1)<kAlmost0) return kFALSE;
+ if (TMath::Abs(r2)<kAlmost0) return kFALSE;
fX=xk;
double dy2dx = (f1+f2)/(r1+r2);
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff