SGCosmic Class Reference

Class to generate tracks in the cosmics generator and store them in a MCParticle graph. More...

#include <SGCosmic.h>

Collaboration diagram for SGCosmic:

Classes
struct	Parameters
	Struct to keep all necessary parameters for the cosmic generator. More...

Public Member Functions
	SGCosmic ()
	Default constructor.
	~SGCosmic ()
	Default destructor.
bool	generateEvent (MCParticleGraph &graph)
	Generates the next event and store the result in the given MCParticle graph. More...
bool	setParameters (const Parameters &parameters)
	Sets the parameters for generating the Particles.

Protected Attributes
Parameters	m_params
	All relevant parameters.

Private Member Functions
double	findMax (const double *dim, const int num)
	Finds maximum value in an array.
void	genCosmic (const int level, int &charge, double &dr, double &phi, double &Pt, double &dz, double &tanl)
	Generates cosmic events according to tabulated distributions in 5-dimensional space: dr, phi, Pt, dz, tanl.
int	muChargeFlag (const double)
	Generates the muon charge according to the positively/negatively charged muon ratio.
void	mkdist_v1 (const int charge, double *)
	Generates distributions in 5-parameter space for different particle charges.
int	mkDr_pos_v1 (const double dr, const float rndm)
	Generates vertex distributions in the radial direction dr by accept-reject method for positively charged particles.
int	mkDr_neg_v1 (const double dr, const float rndm)
	Generates vertex distributions in the radial direction dr by accept-reject method for negatively.
int	mkPhi_pos_v1 (const double phi, const float rndm)
	Generates azimuthal angle phi distributions by accept-reject method for positively charged particles.
int	mkPhi_neg_v1 (const double phi, const float rndm)
	Generates azimuthal angle phi distributions by accept-reject method for negatively charged particles.
int	mkPt_pos_v1 (const double pt, const float rndm)
	Generates transverse momentum pt distributions by accept-reject method for positively charged particles.
int	mkPt_neg_v1 (const double pt, const float rndm)
	Generates transverse momentum pt distributions by accept-reject method for negatively charged particles.
int	mkDz_pos_v1 (const double dz, const float rndm)
	Generates z vertex dz distributions by accept-reject method for positively charged particles.
int	mkDz_neg_v1 (const double dz, const float rndm)
	Generates z vertex dz distributions by accept-reject method for negatively charged particles.
int	mkTanl_pos_v1 (const double tanl, const float rndm)
	Generates tangent of the polar angle tanl distributions by accept-reject method for positively charged particles.
int	mkTanl_neg_v1 (const double tanl, const float rndm)
	Generates tangent of the polar angle tanl distributions by accept-reject method for negatively charged particles.
void	mkdist_v2 (const int charge, double *)
	Generates distributions in 5-parameter space for different particle charges.
int	mkDr_pos_v2 (const double dr, const float rndm)
	Generates vertex distributions in the radial direction dr by accept-reject method for positively charged particles.
int	mkDr_neg_v2 (const double dr, const float rndm)
	Generates vertex distributions in the radial direction dr by accept-reject method for negatively charged particles.
int	mkPhi_pos_v2 (const double phi, const float rndm)
	Generates azimuthal angle phi distributions by accept-reject method for positively charged particles.
int	mkPhi_neg_v2 (const double phi, const float rndm)
	Generates azimuthal angle phi distributions by accept-reject method for negatively charged particles.
int	mkPt_pos_v2 (const double pt, const float rndm)
	Generates transverse momentum pt distributions by accept-reject method for positively charged particles.
int	mkPt_neg_v2 (const double pt, const float rndm)
	Generates transverse momentum pt distributions by accept-reject method for negatively charged particles.
int	mkDz_pos_v2 (const double dz, const float rndm)
	Generates z vertex dz distributions by accept-reject method for positively charged particles.
int	mkDz_neg_v2 (const double dz, const float rndm)
	Generates z vertex dz distributions by accept-reject method for negatively charged particles.
int	mkTanl_pos_v2 (const double tanl, const float rndm)
	Generates tangent of the polar angle tanl distributions by accept-reject method for positively charged particles.
int	mkTanl_neg_v2 (const double tanl, const float rndm)
	Generates tangent of the polar angle tanl distributions by accept-reject method for negatively charged particles.

Detailed Description

Class to generate tracks in the cosmics generator and store them in a MCParticle graph.

The class supports two version (levels) of event generation with IP and pt parameters.

Definition at line 23 of file SGCosmic.h.

Member Function Documentation

generateEvent()

bool generateEvent

(

MCParticleGraph &

graph

)

Generates the next event and store the result in the given MCParticle graph.

Returns

true if the event was generated.

Definition at line 74 of file SGCosmic.cc.

{
  int charge = 0; // Initialization of charge
  double dr, pt, phi, dz, tanl;
 
  while (true) {
 
    genCosmic(m_params.level, charge, dr, phi, pt, dz, tanl);
 
    MCParticleGraph::GraphParticle& p = graph.addParticle();
    p.setStatus(MCParticle::c_PrimaryParticle);
 
    if (1 == charge) {
      p.setPDG(-13);
    } else if (-1 == charge) {
      p.setPDG(13);
    } else {
      continue;
    }
    p.setMassFromPDG();
    p.setFirstDaughter(0);
    p.setLastDaughter(0);
 
#ifdef DEBUG
    if (1 == m_params.level) ofs_cosmic1g << charge << " " << dr << " " << phi << " "
                                            << pt << " " << dz << " " << tanl << endl;
    else if (2 == m_params.level) ofs_cosmic2g << charge << " " << dr << " " << phi << " "
                                                 << pt << " " << dz << " " << tanl << endl;
#endif
 
    // Simulate helix parameter at perigee
    float bz = BFieldManager::getField(0, 0, 0).Z() / Unit::T; // Magnetic field
    const float EPS = 0.0001; // Avoid using zero magnetic field
    if (fabs(bz) < EPS) bz = EPS; // Set the value of the magnetic field to a small number
    float d0, phi0, omega, z0, tanLambda; // The definition is the same as in the Helix class
    d0 = dr;
    phi0 = phi;
    omega = (double)charge / (pt * Helix::getAlpha(bz));
    z0 = dz;
    tanLambda = tanl;
    Helix CosmicMCHelix(d0, phi0, omega, z0, tanLambda);
 
    const float cylindricalR = m_params.cylindricalR; // radius (cm) of generation
    float arcLength;
    // Get arc length at ToP radius
    arcLength = CosmicMCHelix.getArcLength2DAtCylindricalR(cylindricalR);
    if (isnan(arcLength)) continue;
 
    // Calculate coordinates and momentum at ToP radius
    ROOT::Math::XYZVector vector;
    vector = CosmicMCHelix.getPositionAtArcLength2D(- arcLength);
    double vx = vector.x();
    double vy = vector.y();
    double vz = vector.z();
    vector = CosmicMCHelix.getMomentumAtArcLength2D(- arcLength, bz);
    double px = vector.x();
    double py = vector.y();
    double pz = vector.z();
    double m = p.getMass();
    double e  = sqrt(px * px + py * py + pz * pz + m * m);
 
#ifdef DEBUG
    if (1 == m_params.level) ofs_cosmic1c << vx << " " << vy << " " << vz << " "
                                            << px << " " << py << " " << pz << endl;
    else if (2 == m_params.level) ofs_cosmic2c << vx << " " << vy << " " << vz << " "
                                                 << px << " " << py << " " << pz << endl;
#endif
 
    p.setMomentum(px, py, pz);
    p.setEnergy(e);
    p.setProductionVertex(vx, vy, vz);
    p.addStatus(MCParticle::c_StableInGenerator);
 
    return true;
  }
  return false;
}

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The documentation for this class was generated from the following files:

• generators/cosmics/include/SGCosmic.h
• generators/cosmics/src/SGCosmic.cc