message: Do not modify track parameters when computing momentum at decay vertex
diff: @@ -3813,10 +3813,14 @@ Bool_t AliAnalysisVertexingHF::GetTrackMomentumAtSecVert(AliESDtrack* tr, AliAOD
  sn = cs<1. ? tgfv*cs : 0.;
  x = xv*cs + yv*sn;
  - float alpNew = alpha+TMath::ASin(sn);
  - if (!tr->RotateParamOnly(alpNew)) {
  - return kFALSE; // failed
  - }
  - tr->GetPxPyPzAt(x, fBzkG,momentum); // extract momentum
  - return kTRUE;
  + Double_t alpNew = alpha+TMath::ASin(sn);
  + Double_t ca=TMath::Cos(alpNew-alpha), sa=TMath::Sin(alpNew-alpha);
  + Double_t p2=tr->GetSnp();
  + Double_t xNew=tr->GetX()*ca + tr->GetY()*sa;
  + Double_t p2New=p2*ca - TMath::Sqrt((1.- p2)*(1.+p2))*sa;
  + momentum[0]=tr->GetSigned1Pt();
  + momentum[1]=p2New*(x-xNew)*tr->GetC(fBzkG);
  + momentum[2]=tr->GetTgl();
  + Bool_t retCode=tr->Local2GlobalMomentum(momentum,alpNew);
  + return retCode;
  }
  