| 1 | /*
|
|---|
| 2 | * ---- Delphes ----
|
|---|
| 3 | * A Fast Simulator for general purpose LHC detector
|
|---|
| 4 | * S. Ovyn ~~~~ severine.ovyn@uclouvain.be
|
|---|
| 5 | *
|
|---|
| 6 | * Center for Particle Physics and Phenomenology (CP3)
|
|---|
| 7 | * Universite Catholique de Louvain (UCL)
|
|---|
| 8 | * Louvain-la-Neuve, Belgium
|
|---|
| 9 | * */
|
|---|
| 10 |
|
|---|
| 11 | #include "interface/BFieldProp.h"
|
|---|
| 12 | #include "TRandom.h"
|
|---|
| 13 |
|
|---|
| 14 | #include <iostream>
|
|---|
| 15 | #include <sstream>
|
|---|
| 16 | #include <fstream>
|
|---|
| 17 | #include <iomanip>
|
|---|
| 18 |
|
|---|
| 19 | #include<cmath>
|
|---|
| 20 |
|
|---|
| 21 |
|
|---|
| 22 | using namespace std;
|
|---|
| 23 |
|
|---|
| 24 |
|
|---|
| 25 | //------------------------------------------------------------------------------
|
|---|
| 26 |
|
|---|
| 27 | TrackPropagation::TrackPropagation() {
|
|---|
| 28 |
|
|---|
| 29 | MAXITERATION = 10000;
|
|---|
| 30 | MINSEGLENGTH = 70;
|
|---|
| 31 |
|
|---|
| 32 | }
|
|---|
| 33 |
|
|---|
| 34 | void TrackPropagation::Propagation(const TRootGenParticle *Part,TLorentzVector &genMomentum)
|
|---|
| 35 | {
|
|---|
| 36 |
|
|---|
| 37 | double q = Charge(Part->PID);
|
|---|
| 38 | if(q==0)return;
|
|---|
| 39 |
|
|---|
| 40 | float Xvertex1 = Part->X;
|
|---|
| 41 | float Yvertex1 = Part->Y;
|
|---|
| 42 | float Zvertex1 = Part->Z;
|
|---|
| 43 |
|
|---|
| 44 | //out of trackibg coverage?
|
|---|
| 45 | if(sqrt(Xvertex1*Xvertex1+Yvertex1*Yvertex1) > TRACKING_RADIUS){return;}
|
|---|
| 46 | if(fabs(Zvertex1) > TRACKING_LENGTH){return;}
|
|---|
| 47 |
|
|---|
| 48 | float Px = Part->Px;
|
|---|
| 49 | float Py = Part->Py;
|
|---|
| 50 | float Pz = Part->Pz;
|
|---|
| 51 |
|
|---|
| 52 | double px = Px / 0.003;
|
|---|
| 53 | double py = Py / 0.003;
|
|---|
| 54 | double pz = Pz / 0.003;
|
|---|
| 55 | double pt = sqrt(px*px+py*py);
|
|---|
| 56 | double p = sqrt(px*px+py*py+pz*pz);
|
|---|
| 57 |
|
|---|
| 58 | if(q!=0){
|
|---|
| 59 | double M = Part->M;
|
|---|
| 60 | double vx = px/M;
|
|---|
| 61 | double vy = py/M;
|
|---|
| 62 | double vz = pz/M;
|
|---|
| 63 |
|
|---|
| 64 | double Bx = BFIELD_X;
|
|---|
| 65 | double By = BFIELD_Y;
|
|---|
| 66 | double Bz = BFIELD_Z;
|
|---|
| 67 |
|
|---|
| 68 | double ax = (q/M)*(Bz*vy - By*vz);
|
|---|
| 69 | double ay = (q/M)*(Bx*vz - Bz*vx);
|
|---|
| 70 | double az = (q/M)*(By*vx - Bx*vy);
|
|---|
| 71 | double dt = 1/p;
|
|---|
| 72 | if(pt<266 && vz < 0.0012) dt = fabs(0.001/vz);
|
|---|
| 73 |
|
|---|
| 74 | double xold=Xvertex1; double x=xold;
|
|---|
| 75 | double yold=Yvertex1; double y=yold;
|
|---|
| 76 | double zold=Zvertex1; double z=zold;
|
|---|
| 77 |
|
|---|
| 78 | double VTold = sqrt(vx*vx+vy*vy);
|
|---|
| 79 |
|
|---|
| 80 | int k = 0;
|
|---|
| 81 |
|
|---|
| 82 | while(k < MAXITERATION){
|
|---|
| 83 | k++;
|
|---|
| 84 |
|
|---|
| 85 | vx += ax*dt;
|
|---|
| 86 | vy += ay*dt;
|
|---|
| 87 | vz += az*dt;
|
|---|
| 88 |
|
|---|
| 89 | double VTratio = VTold/sqrt(vx*vx+vy*vy);
|
|---|
| 90 | vx *= VTratio;
|
|---|
| 91 | vy *= VTratio;
|
|---|
| 92 |
|
|---|
| 93 | ax = (q/M)*(Bz*vy - By*vz);
|
|---|
| 94 | ay = (q/M)*(Bx*vz - Bz*vx);
|
|---|
| 95 | az = (q/M)*(By*vx - Bx*vy);
|
|---|
| 96 |
|
|---|
| 97 | x += vx*dt;
|
|---|
| 98 | y += vy*dt;
|
|---|
| 99 | z += vz*dt;
|
|---|
| 100 |
|
|---|
| 101 | if( (x*x+y*y) > TRACKING_RADIUS*TRACKING_RADIUS ){ x /= (x*x+y*y)/(TRACKING_RADIUS*TRACKING_RADIUS); y /= (x*x+y*y)/(TRACKING_RADIUS*TRACKING_RADIUS); break;}
|
|---|
| 102 | if( fabs(z)>TRACKING_LENGTH)break;
|
|---|
| 103 |
|
|---|
| 104 | xold = x;
|
|---|
| 105 | yold = y;
|
|---|
| 106 | zold = z;
|
|---|
| 107 | }
|
|---|
| 108 |
|
|---|
| 109 | if(x!=0 && y!=0 && z!=0)
|
|---|
| 110 | {
|
|---|
| 111 | double eta;
|
|---|
| 112 | float Theta = atan2(sqrt(x*x+y*y),z);
|
|---|
| 113 | eta = -log(tan(Theta/2));
|
|---|
| 114 | double phi = atan2(y,x);
|
|---|
| 115 | genMomentum.SetPtEtaPhiE(Part->PT,eta,phi,Part->E);
|
|---|
| 116 | }
|
|---|
| 117 | }
|
|---|
| 118 | }
|
|---|
