SingleParticleEvent.cc

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#include "GeneratorInterface/CosmicMuonGenerator/interface/SingleParticleEvent.h"

void SingleParticleEvent::create(
    int id, double px, double py, double pz, double e, double m, double vx, double vy, double vz, double t0) {
  ID = ID_in = id;
  Px = Px_in = px;
  Py = Py_in = py;
  Pz = Pz_in = pz;
  E = E_in = e;
  M = M_in = m;
  Vx = Vx_in = vx;
  Vy = Vy_in = vy;
  Vz = Vz_in = vz;
  T0 = T0_in = t0;
  HitTarget = false;
}

void SingleParticleEvent::propagate(double ElossScaleFac,
                                    double RadiusTarget,
                                    double Z_DistTarget,
                                    double Z_CentrTarget,
                                    bool TrackerOnly,
                                    bool MTCCHalf) {
  MTCC = MTCCHalf;  //need to know this boolean in absVzTmp()
  // calculated propagation direction
  dX = Px / absmom();
  dY = Py / absmom();
  dZ = Pz / absmom();
  // propagate with decreasing step size
  tmpVx = Vx;
  tmpVy = Vy;
  tmpVz = Vz;
  double RadiusTargetEff = RadiusTarget;
  double Z_DistTargetEff = Z_DistTarget;
  double Z_CentrTargetEff = Z_CentrTarget;
  if (TrackerOnly == true) {
    RadiusTargetEff = RadiusTracker;
    Z_DistTargetEff = Z_DistTracker;
  }
  HitTarget = true;
  if (HitTarget == true) {
    HitTarget = false;
    double stepSize = MinStepSize * 100000.;
    double acceptR = RadiusTargetEff + stepSize;
    double acceptZ = Z_DistTargetEff + stepSize;
    bool continuePropagation = true;
    while (continuePropagation) {
      //if (tmpVy < -acceptR) continuePropagation = false;
      if (dY < 0. && tmpVy < -acceptR)
        continuePropagation = false;
      if (dY >= 0. && tmpVy > acceptR)
        continuePropagation = false;
      //if (absVzTmp() < acceptZ && rVxyTmp() < acceptR){
      if (std::fabs(tmpVz - Z_CentrTargetEff) < acceptZ && rVxyTmp() < acceptR) {
        HitTarget = true;
        continuePropagation = false;
      }
      if (continuePropagation)
        updateTmp(stepSize);
    }
  }
  if (HitTarget == true) {
    HitTarget = false;
    double stepSize = MinStepSize * 10000.;
    double acceptR = RadiusTargetEff + stepSize;
    double acceptZ = Z_DistTargetEff + stepSize;
    bool continuePropagation = true;
    while (continuePropagation) {
      //if (tmpVy < -acceptR) continuePropagation = false;
      if (dY < 0. && tmpVy < -acceptR)
        continuePropagation = false;
      if (dY >= 0. && tmpVy > acceptR)
        continuePropagation = false;
      //if (absVzTmp() < acceptZ && rVxyTmp() < acceptR){
      if (std::fabs(tmpVz - Z_CentrTargetEff) < acceptZ && rVxyTmp() < acceptR) {
        HitTarget = true;
        continuePropagation = false;
      }
      if (continuePropagation)
        updateTmp(stepSize);
    }
  }
  if (HitTarget == true) {
    HitTarget = false;
    double stepSize = MinStepSize * 1000.;
    double acceptR = RadiusTargetEff + stepSize;
    double acceptZ = Z_DistTargetEff + stepSize;
    bool continuePropagation = true;
    while (continuePropagation) {
      //if (tmpVy < -acceptR) continuePropagation = false;
      if (dY < 0. && tmpVy < -acceptR)
        continuePropagation = false;
      if (dY >= 0. && tmpVy > acceptR)
        continuePropagation = false;
      //if (absVzTmp() < acceptZ && rVxyTmp() < acceptR){
      if (std::fabs(tmpVz - Z_CentrTargetEff) < acceptZ && rVxyTmp() < acceptR) {
        HitTarget = true;
        continuePropagation = false;
      }
      if (continuePropagation)
        updateTmp(stepSize);
    }
  }
  if (HitTarget == true) {
    HitTarget = false;
    double stepSize = MinStepSize * 100.;
    double acceptR = RadiusTargetEff + stepSize;
    double acceptZ = Z_DistTargetEff + stepSize;
    bool continuePropagation = true;
    while (continuePropagation) {
      //if (tmpVy < -acceptR) continuePropagation = false;
      if (dY < 0. && tmpVy < -acceptR)
        continuePropagation = false;
      if (dY >= 0. && tmpVy > acceptR)
        continuePropagation = false;
      //if (absVzTmp() < acceptZ && rVxyTmp() < acceptR){
      if (std::fabs(tmpVz - Z_CentrTargetEff) < acceptZ && rVxyTmp() < acceptR) {
        HitTarget = true;
        continuePropagation = false;
      }
      if (continuePropagation)
        updateTmp(stepSize);
    }
  }
  if (HitTarget == true) {
    HitTarget = false;
    double stepSize = MinStepSize * 10.;
    double acceptR = RadiusTargetEff + stepSize;
    double acceptZ = Z_DistTargetEff + stepSize;
    bool continuePropagation = true;
    while (continuePropagation) {
      //if (tmpVy < -acceptR) continuePropagation = false;
      if (dY < 0. && tmpVy < -acceptR)
        continuePropagation = false;
      if (dY >= 0. && tmpVy > acceptR)
        continuePropagation = false;
      //if (absVzTmp() < acceptZ && rVxyTmp() < acceptR){
      if (std::fabs(tmpVz - Z_CentrTargetEff) < acceptZ && rVxyTmp() < acceptR) {
        HitTarget = true;
        continuePropagation = false;
      }
      if (continuePropagation)
        updateTmp(stepSize);
    }
  }
  if (HitTarget == true) {
    HitTarget = false;
    double stepSize = MinStepSize * 1.;
    double acceptR = RadiusTargetEff + stepSize;
    double acceptZ = Z_DistTargetEff + stepSize;
    bool continuePropagation = true;
    while (continuePropagation) {
      //if (tmpVy < -acceptR) continuePropagation = false;
      if (dY < 0. && tmpVy < -acceptR)
        continuePropagation = false;
      if (dY >= 0. && tmpVy > acceptR)
        continuePropagation = false;
      //if (0 < absVzTmp()){ //only check for MTCC setup in last step of propagation, need fine stepSize
      if (absVzTmp() < acceptZ && rVxyTmp() < acceptR) {
        if (std::fabs(tmpVz - Z_CentrTargetEff) < acceptZ && rVxyTmp() < acceptR) {
          HitTarget = true;
          continuePropagation = false;
        }
      }
      if (continuePropagation)
        updateTmp(stepSize);
    }
  }
  // actual propagation + energy loss
  if (HitTarget == true) {
    HitTarget = false;
    //int nAir = 0; int nWall = 0; int nRock = 0; int nClay = 0; int nPlug = 0;
    int nMat[6] = {0, 0, 0, 0, 0, 0};
    double stepSize = MinStepSize * 1.;  // actual step size
    double acceptR = RadiusCMS + stepSize;
    double acceptZ = Z_DistCMS + stepSize;
    if (TrackerOnly == true) {
      acceptR = RadiusTracker + stepSize;
      acceptZ = Z_DistTracker + stepSize;
    }
    bool continuePropagation = true;
    while (continuePropagation) {
      //if (Vy < -acceptR) continuePropagation = false;
      if (dY < 0. && tmpVy < -acceptR)
        continuePropagation = false;
      if (dY >= 0. && tmpVy > acceptR)
        continuePropagation = false;
      //if (absVz() < acceptZ && rVxy() < acceptR){
      if (std::fabs(Vz - Z_CentrTargetEff) < acceptZ && rVxy() < acceptR) {
        HitTarget = true;
        continuePropagation = false;
      }
      if (continuePropagation)
        update(stepSize);

      int Mat = inMat(Vx, Vy, Vz, PlugVx, PlugVz, ClayWidth);

      nMat[Mat]++;
    }

    if (HitTarget) {
      double lPlug = double(nMat[Plug]) * stepSize;
      double lWall = double(nMat[Wall]) * stepSize;
      double lAir = double(nMat[Air]) * stepSize;
      double lClay = double(nMat[Clay]) * stepSize;
      double lRock = double(nMat[Rock]) * stepSize;
      //double lUnknown = double(nMat[Unknown])*stepSize;

      double waterEquivalents =
          (lAir * RhoAir + lWall * RhoWall + lRock * RhoRock + lClay * RhoClay + lPlug * RhoPlug) * ElossScaleFac /
          10.;  // [g cm^-2]
      subtractEloss(waterEquivalents);
      if (E < MuonMass)
        HitTarget = false;  // muon stopped in the material around the target
    }
  }
  // end of propagation part
}

void SingleParticleEvent::update(double stepSize) {
  Vx += stepSize * dX;
  Vy += stepSize * dY;
  Vz += stepSize * dZ;
}

void SingleParticleEvent::updateTmp(double stepSize) {
  tmpVx += stepSize * dX;
  tmpVy += stepSize * dY;
  tmpVz += stepSize * dZ;
}

void SingleParticleEvent::subtractEloss(double waterEquivalents) {
  double L10E = log10(E);
  // parameters for standard rock (PDG 2004, page 230)
  double A = (1.91514 + 0.254957 * L10E) / 1000.;                              // a [GeV g^-1 cm^2]
  double B = (0.379763 + 1.69516 * L10E - 0.175026 * L10E * L10E) / 1000000.;  // b [g^-1 cm^2]
  double EPS = A / B;                                                          // epsilon [GeV]
  E = (E + EPS) * exp(-B * waterEquivalents) - EPS;                            // updated energy
  double oldAbsMom = absmom();
  double newAbsMom = sqrt(E * E - MuonMass * MuonMass);
  Px = Px * newAbsMom / oldAbsMom;  // updated px
  Py = Py * newAbsMom / oldAbsMom;  // updated py
  Pz = Pz * newAbsMom / oldAbsMom;  // updated pz
}

double SingleParticleEvent::Eloss(double waterEquivalents, double Energy) {
  double L10E = log10(Energy);
  // parameters for standard rock (PDG 2004, page 230)
  double A = (1.91514 + 0.254957 * L10E) / 1000.;                              // a [GeV g^-1 cm^2]
  double B = (0.379763 + 1.69516 * L10E - 0.175026 * L10E * L10E) / 1000000.;  // b [g^-1 cm^2]
  double EPS = A / B;                                                          // epsilon [GeV]
  double newEnergy = (Energy + EPS) * exp(-B * waterEquivalents) - EPS;        // updated energy
  double EnergyLoss = Energy - newEnergy;
  return EnergyLoss;
}

void SingleParticleEvent::setEug(double Eug) { E_ug = Eug; }

double SingleParticleEvent::Eug() { return E_ug; }

double SingleParticleEvent::deltaEmin(double E_sf) {
  double dE = Eloss(waterEquivalents, E_sf);
  return E_ug - (E_sf - dE);
}

void SingleParticleEvent::SurfProj(double Vx_in,
                                   double Vy_in,
                                   double Vz_in,
                                   double Px_in,
                                   double Py_in,
                                   double Pz_in,
                                   double& Vx_up,
                                   double& Vy_up,
                                   double& Vz_up) {
  //determine vertex of muon at Surface (+PlugWidth)
  double dy = Vy_in - (SurfaceOfEarth + PlugWidth);
  Vy_up = Vy_in - dy;
  Vx_up = Vx_in - dy * Px_in / Py_in;
  Vz_up = Vz_in - dy * Pz_in / Py_in;
  if (Debug)
    std::cout << "Vx_up=" << Vx_up << " Vy_up=" << Vy_up << " Vz_up=" << Vz_up << std::endl;
}

double SingleParticleEvent::absVzTmp() {
  if (MTCC == true) {
    return tmpVz;  //need sign to be sure muon hits half of CMS with MTCC setup
  } else {
    return std::fabs(tmpVz);
  }
}

double SingleParticleEvent::rVxyTmp() { return sqrt(tmpVx * tmpVx + tmpVy * tmpVy); }

bool SingleParticleEvent::hitTarget() { return HitTarget; }

int SingleParticleEvent::id_in() { return ID_in; }

double SingleParticleEvent::px_in() { return Px_in; }

double SingleParticleEvent::py_in() { return Py_in; }

double SingleParticleEvent::pz_in() { return Pz_in; }

double SingleParticleEvent::e_in() { return E_in; }

double SingleParticleEvent::m_in() { return M_in; }

double SingleParticleEvent::vx_in() { return Vx_in; }

double SingleParticleEvent::vy_in() { return Vy_in; }

double SingleParticleEvent::vz_in() { return Vz_in; }

double SingleParticleEvent::t0_in() { return T0_in; }

int SingleParticleEvent::id() { return ID; }

double SingleParticleEvent::px() { return Px; }

double SingleParticleEvent::py() { return Py; }

double SingleParticleEvent::pz() { return Pz; }

double SingleParticleEvent::e() { return E; }

double SingleParticleEvent::m() { return M; }

double SingleParticleEvent::vx() { return Vx; }

double SingleParticleEvent::vy() { return Vy; }

double SingleParticleEvent::vz() { return Vz; }

double SingleParticleEvent::t0() { return T0; }

double SingleParticleEvent::WaterEquivalents() { return waterEquivalents; }

double SingleParticleEvent::phi() {
  double phiXZ = atan2(Px, Pz);
  if (phiXZ < 0.)
    phiXZ = phiXZ + TwoPi;
  return phiXZ;
}

double SingleParticleEvent::theta() { return atan2(sqrt(Px * Px + Pz * Pz), -Py); }

double SingleParticleEvent::absmom() { return sqrt(Px * Px + Py * Py + Pz * Pz); }

double SingleParticleEvent::absVz() { return std::fabs(Vz); }

double SingleParticleEvent::rVxy() { return sqrt(Vx * Vx + Vy * Vy); }