G4AngularDistribution Class Reference

#include <G4AngularDistribution.hh>

Inheritance diagram for G4AngularDistribution:

Public Member Functions
	G4AngularDistribution (G4bool symmetrize)
virtual	~G4AngularDistribution ()
virtual G4double	CosTheta (G4double s, G4double m1, G4double m2) const
G4double	DifferentialCrossSection (G4double sIn, G4double m1, G4double m2, G4double cosTheta) const
G4double	Cross (G4double tpPion, G4double tpSigma, G4double tpOmega, G4double tmPion, G4double tmSigma, G4double tmOmega, G4double bMix_o1, G4double bMix_s1, G4double bMix_Omega, G4double bMix_sm, G4double bMix_oL, G4double bMix_sL, G4double bOmega_0, G4double bOmega_1, G4double bOmega_2, G4double bOmega_3, G4double bOmega_m, G4double bOmega_L) const
Public Member Functions inherited from G4VAngularDistribution
	G4VAngularDistribution ()
virtual	~G4VAngularDistribution ()
virtual G4double	Phi () const

Detailed Description

Definition at line 42 of file G4AngularDistribution.hh.

Constructor & Destructor Documentation

G4AngularDistribution::G4AngularDistribution

(

G4bool

symmetrize

)

Definition at line 33 of file G4AngularDistribution.cc.

  : sym(symmetrize)
{
  // The following are parameters of the model - not to be confused with the PDG values!

      mSigma = 0.55; 
      cmSigma = 1.20; 
      gSigma  = 9.4;

      mOmega = 0.783; 
      cmOmega = 0.808; 
      gOmega = 10.95;

      mPion = 0.138; 
      cmPion = 0.51; 
      gPion  = 7.27;

      mNucleon = 0.938;   

      // Definition of constants for pion-Term (no s-dependence)

      m42   = 4. * mNucleon * mNucleon;
      mPion2  = mPion * mPion;           
      cmPion2 = cmPion * cmPion;
      dPion1 = cmPion2-mPion2;
      dPion2 = dPion1 * dPion1;
      cm6gp = 1.5 * (cmPion2*cmPion2*cmPion2) * (gPion*gPion*gPion*gPion) * m42 * m42 / dPion2;

      cPion_3 = -(cm6gp/3.);
      cPion_2 = -(cm6gp * mPion2/dPion1);
      cPion_1 = -(cm6gp * mPion2 * (2. * cmPion2 + mPion2) / dPion2);
      cPion_m = -(cm6gp * cmPion2 * mPion2 / dPion2);
      cPion_L = -(cm6gp * 2. * cmPion2 * mPion2 * (cmPion2 + mPion2) / dPion2 / dPion1);
      cPion_0 = -(cPion_3 + cPion_2 + cPion_1 + cPion_m);
    
     // Definition of constants for sigma-Term (no s-dependence)

      G4double gSigmaSq = gSigma * gSigma; 

      mSigma2  = mSigma * mSigma;
      cmSigma2 = cmSigma * cmSigma;
      cmSigma4 = cmSigma2 * cmSigma2;
      cmSigma6 = cmSigma2 * cmSigma4;
      dSigma1 = m42 - cmSigma2;
      dSigma2 = m42 - mSigma2;
      dSigma3 = cmSigma2 - mSigma2;

      G4double dSigma1Sq = dSigma1 * dSigma1;
      G4double dSigma2Sq = dSigma2 * dSigma2;
      G4double dSigma3Sq = dSigma3 * dSigma3;

      cm2gs = 0.5 * cmSigma2 * gSigmaSq*gSigmaSq / dSigma3Sq;     


      cSigma_3 = -(cm2gs * dSigma1Sq / 3.);
      cSigma_2 = -(cm2gs * cmSigma2 * dSigma1 * dSigma2 / dSigma3);
      cSigma_1 = -(cm2gs * cmSigma4 * (2. * dSigma1 + dSigma2) * dSigma2 / dSigma3Sq);
      cSigma_m = -(cm2gs * cmSigma6 * dSigma2Sq / mSigma2 / dSigma3Sq);
      cSigma_L = -(cm2gs * cmSigma6 * dSigma2 * (dSigma1 + dSigma2) * 2. / (dSigma3 * dSigma3Sq));
      cSigma_0 = -(cSigma_3 + cSigma_2 + cSigma_1 + cSigma_m);

      // Definition of constants for omega-Term

      G4double gOmegaSq = gOmega * gOmega;

      mOmega2  = mOmega * mOmega;
      cmOmega2 = cmOmega * cmOmega;
      cmOmega4 = cmOmega2 * cmOmega2;
      cmOmega6 = cmOmega2 * cmOmega4;
      dOmega1 = m42 - cmOmega2;
      dOmega2 = m42 - mOmega2;
      dOmega3 = cmOmega2 - mOmega2;
      sOmega1 = cmOmega2 + mOmega2;

      G4double dOmega3Sq = dOmega3 * dOmega3;

      cm2go = 0.5 * cmOmega2 * gOmegaSq * gOmegaSq / dOmega3Sq;

      cOmega_3 =  cm2go / 3.;
      cOmega_2 = -(cm2go * cmOmega2 / dOmega3);
      cOmega_1 =  cm2go * cmOmega4 / dOmega3Sq;
      cOmega_m =  cm2go * cmOmega6 / (dOmega3Sq * mOmega2);
      cOmega_L = -(cm2go * cmOmega6 * 4. / (dOmega3 * dOmega3Sq));

      // Definition of constants for mix-Term

      G4double fac1Tmp = (gSigma * gOmega * cmSigma2 * cmOmega2);
      fac1 = -(fac1Tmp *  fac1Tmp * m42);  
      dMix1 = cmOmega2 - cmSigma2;
      dMix2 = cmOmega2 - mSigma2;
      dMix3 = cmSigma2 - mOmega2;

      G4double dMix1Sq = dMix1 * dMix1;
      G4double dMix2Sq = dMix2 * dMix2;
      G4double dMix3Sq = dMix3 * dMix3;

      cMix_o1 =    fac1 / (cmOmega2  * dMix1Sq * dMix2 * dOmega3);
      cMix_s1 =    fac1 / (cmSigma2  * dMix1Sq * dMix3 * dSigma3);
      cMix_Omega = fac1 / (dOmega3Sq * dMix3Sq * (mOmega2 - mSigma2));
      cMix_sm =    fac1 / (dSigma3Sq * dMix2Sq * (mSigma2 - mOmega2)); 
      fac2 = (-fac1) / (dMix1*dMix1Sq * dOmega3Sq * dMix2Sq);
      fac3 = (-fac1) / (dMix1*dMix1Sq * dSigma3Sq * dMix3Sq); 
      
      cMix_oLc = fac2 * (3. * cmOmega2*cmOmega4            - cmOmega4 * cmSigma2 
               - 2. * cmOmega4 * mOmega2           - 2. * cmOmega4 * mSigma2 
               + cmOmega2 * mOmega2 * mSigma2      + cmSigma2 * mOmega2 * mSigma2 
               - 4. * cmOmega4 * m42               + 2. * cmOmega2 * cmSigma2 * m42 
               + 3. * cmOmega2 * mOmega2 * m42     - cmSigma2 * mOmega2 * m42 
               + 3. * cmOmega2 * mSigma2 * m42     - cmSigma2 * mSigma2 * m42 
               - 2. * mOmega2 * mSigma2 * m42);
      
      cMix_oLs = fac2 * (8. * cmOmega4                     - 4. * cmOmega2 * cmSigma2 
             - 6. * cmOmega2 * mOmega2         + 2. * cmSigma2 * mOmega2 
             - 6. * cmOmega2 * mSigma2         + 2. * cmSigma2 * mSigma2 
             + 4. * mOmega2 * mSigma2);
      
      cMix_sLc = fac3 * (cmOmega2 * cmSigma4               - 3. * cmSigma6    
             + 2. * cmSigma4 * mOmega2         + 2. * cmSigma4 * mSigma2 
             - cmOmega2 * mOmega2 * mSigma2    - cmSigma2 * mOmega2 * mSigma2 
             - 2. * cmOmega2 * cmSigma2 * m42  + 4. * cmSigma4 * m42 
             + cmOmega2 * mOmega2 * m42        - 3. * cmSigma2 * mOmega2 * m42 
             + cmOmega2 * mSigma2 * m42        - 3. * cmSigma2 * mSigma2 * m42 
             + 2. * mOmega2 * mSigma2 * m42);

      cMix_sLs = fac3 * (4. * cmOmega2 * cmSigma2          - 8. * cmSigma4
               - 2. * cmOmega2 * mOmega2           + 6. * cmSigma2 * mOmega2 
               - 2. * cmOmega2 * mSigma2           + 6. * cmSigma2 * mSigma2 
               - 4. * mOmega2 * mSigma2);
}

G4AngularDistribution::~G4AngularDistribution ( )

virtual

Definition at line 165 of file G4AngularDistribution.cc.

{ }

Member Function Documentation

G4double G4AngularDistribution::CosTheta ( G4double  s, G4double  m1, G4double  m2  ) const

virtual

Implements G4VAngularDistribution.

Definition at line 169 of file G4AngularDistribution.cc.

References DifferentialCrossSection(), and G4UniformRand.

{
   G4double random = G4UniformRand();
   G4double dCosTheta = 2.;
   G4double cosTheta = -1.;

   // For jmax=12 the accuracy is better than 0.1 degree 
   G4int jMax = 12;

   for (G4int j = 1; j <= jMax; ++j)
   {
      // Accuracy is 2^-jmax 
      dCosTheta *= 0.5;
      G4double cosTh = cosTheta + dCosTheta;
      if(DifferentialCrossSection(S, m_1, m_2, cosTh) <= random) cosTheta = cosTh;
    }

   // Randomize in final interval in order to avoid discrete angles 
   cosTheta += G4UniformRand() * dCosTheta;


   if (cosTheta > 1. || cosTheta < -1.)
     throw G4HadronicException(__FILE__, __LINE__, "G4AngularDistribution::CosTheta - std::cos(theta) outside allowed range");

   return cosTheta;
}

G4double G4AngularDistribution::Cross	(	G4double	tpPion,
		G4double	tpSigma,
		G4double	tpOmega,
		G4double	tmPion,
		G4double	tmSigma,
		G4double	tmOmega,
		G4double	bMix_o1,
		G4double	bMix_s1,
		G4double	bMix_Omega,
		G4double	bMix_sm,
		G4double	bMix_oL,
		G4double	bMix_sL,
		G4double	bOmega_0,
		G4double	bOmega_1,
		G4double	bOmega_2,
		G4double	bOmega_3,
		G4double	bOmega_m,
		G4double	bOmega_L
	)		const

Definition at line 294 of file G4AngularDistribution.cc.

Referenced by DifferentialCrossSection().

{
  G4double cross = 0;
     //  Pion
    cross += ((cPion_3 * tpPion  + cPion_2)  * tpPion  + cPion_1)  * tpPion  + cPion_m/tmPion   + cPion_0  +  cPion_L * std::log(tpPion*tmPion);
//    G4cout << "cross1 "<< cross<<G4endl;
    //  Sigma
    cross += ((cSigma_3 * tpSigma + cSigma_2) * tpSigma + cSigma_1) * tpSigma + cSigma_m/tmSigma + cSigma_0 + cSigma_L * std::log(tpSigma*tmSigma);
//    G4cout << "cross2 "<< cross<<G4endl;
    // Omega
    cross += ((bOmega_3 * tpOmega + bOmega_2) * tpOmega + bOmega_1) * tpOmega + bOmega_m/tmOmega + bOmega_0 + bOmega_L * std::log(tpOmega*tmOmega)
    // Mix
    +  bMix_o1 * (tpOmega - 1.)
    +  bMix_s1 * (tpSigma - 1.)
    +  bMix_Omega * std::log(tmOmega)
    +  bMix_sm * std::log(tmSigma)
    +  bMix_oL * std::log(tpOmega)
    +  bMix_sL * std::log(tpSigma);
/*      G4cout << "cross3 "<< cross<<" "
             <<bMix_o1<<" "
             <<bMix_s1<<" "
             <<bMix_Omega<<" "
             <<bMix_sm<<" "
             <<bMix_oL<<" "
             <<bMix_sL<<" "
             <<tpOmega<<" "
             <<tpSigma<<" "
             <<tmOmega<<" "
             <<tmSigma<<" "
             <<tpOmega<<" "
             <<tpSigma
             <<G4endl;
*/
  return cross;

}

G4double G4AngularDistribution::DifferentialCrossSection	(	G4double	sIn,
		G4double	m1,
		G4double	m2,
		G4double	cosTheta
	)		const

Definition at line 197 of file G4AngularDistribution.cc.

References Cross(), python.hepunit::GeV, sqr(), and G4InuclParticleNames::tp.

Referenced by CosTheta().

{
// local calculus is in GeV, ie. normalize input
  sIn = sIn/sqr(GeV)+m42/2.;
  m_1  = m_1/GeV;
  m_2  = m_2/GeV;
//  G4cout << "Here we go"<<sIn << " "<<m1 << " " << m2 <<" " m42<< G4endl;
// scaling from masses other than p,p.
  G4double S = sIn - (m_1+m_2) * (m_1+m_2) + m42;
  G4double tMax = S - m42;
  G4double tp = 0.5 * (cosTheta + 1.) * tMax; 
  G4double twoS = 2. * S;
  
  // Define s-dependent stuff for omega-Term
  G4double brak1 = (twoS-m42) * (twoS-m42);
  G4double bOmega_3 = cOmega_3 * (-2. * cmOmega4 - 2. * cmOmega2 * twoS - brak1);
  G4double bOmega_2 = cOmega_2 * ( 2. * cmOmega2 * mOmega2 + sOmega1 * twoS + brak1);
  G4double bOmega_1 = cOmega_1 * (-4. * cmOmega2 * mOmega2 
             - 2. * mOmega2*mOmega2 
             - 2. * (cmOmega2 + 2 * mOmega2) * twoS 
             - 3. * brak1);
  G4double bOmega_m = cOmega_m * (-2. * mOmega2*mOmega2 - 2. * mOmega2 * twoS - brak1);
  G4double bOmega_L = cOmega_L * (sOmega1 * mOmega2 + (cmOmega2 + 3. * mOmega2) * S + brak1);
  G4double bOmega_0 = -(bOmega_3 + bOmega_2 + bOmega_1 + bOmega_m);
  
  // Define s-dependent stuff for mix-Term            
  G4double bMix_o1 = cMix_o1 * (dOmega1 - twoS);
  G4double bMix_s1 = cMix_s1 * (dSigma1 - twoS);
  G4double bMix_Omega = cMix_Omega * (dOmega2 - twoS);
  G4double bMix_sm = cMix_sm * (dSigma2 - twoS);
  G4double bMix_oL = cMix_oLc + cMix_oLs * S;
  G4double bMix_sL = cMix_sLc + cMix_sLs * S;
  
  G4double t1_Pion = 1. / (1. + tMax / cmPion2);
  G4double t2_Pion = 1. + tMax / mPion2;
  G4double t1_Sigma = 1. / (1. + tMax / cmSigma2);
  G4double t2_Sigma = 1. + tMax / mSigma2;
  G4double t1_Omega = 1. / (1. + tMax / cmOmega2);
  G4double t2_Omega = 1. + tMax / mOmega2;
  
  G4double norm = Cross(t1_Pion, t1_Sigma, t1_Omega,
            t2_Pion, t2_Sigma, t2_Omega,
            bMix_o1, bMix_s1, bMix_Omega,
            bMix_sm, bMix_oL, bMix_sL,
            bOmega_0, bOmega_1, bOmega_2,
            bOmega_3, bOmega_m, bOmega_L);
  
  t1_Pion = 1. / (1. + tp / cmPion2);
  t2_Pion = 1. + tp / mPion2;
  t1_Sigma = 1. / (1. + tp / cmSigma2);
  t2_Sigma = 1. + tp / mSigma2;
  t1_Omega = 1. / (1. + tp / cmOmega2);
  t2_Omega = 1. + tp / mOmega2;
  
  G4double dSigma;
  if (sym) 
    { 
      G4double to;
      norm = 2. * norm;
      to = tMax - tp;
      G4double t3_Pion = 1. / (1. + to / cmPion2);
      G4double t4_Pion = 1. + to / mPion2;
      G4double t3_Sigma = 1. / (1. + to / cmSigma2);
      G4double t4_Sigma = 1. + to / mSigma2;
      G4double t3_Omega = 1. / (1. + to / cmOmega2);
      G4double t4_Omega = 1. + to / mOmega2;
      
      dSigma = ( Cross(t1_Pion, t1_Sigma, t1_Omega,
               t2_Pion,t2_Sigma, t2_Omega,
               bMix_o1, bMix_s1, bMix_Omega,
               bMix_sm, bMix_oL, bMix_sL,
               bOmega_0, bOmega_1, bOmega_2,
               bOmega_3, bOmega_m, bOmega_L) - 
         Cross(t3_Pion,t3_Sigma, t3_Omega,
               t4_Pion, t4_Sigma, t4_Omega,
               bMix_o1, bMix_s1, bMix_Omega,
               bMix_sm, bMix_oL, bMix_sL,
               bOmega_0, bOmega_1, bOmega_2,
               bOmega_3, bOmega_m, bOmega_L) ) 
    / norm + 0.5;
    }
  else
    {
      dSigma = Cross(t1_Pion, t1_Sigma, t1_Omega, 
             t2_Pion, t2_Sigma, t2_Omega,
             bMix_o1, bMix_s1, bMix_Omega,
             bMix_sm, bMix_oL, bMix_sL,
             bOmega_0, bOmega_1, bOmega_2,
             bOmega_3, bOmega_m, bOmega_L) 
    / norm;
    }
  
  return dSigma;
}

---

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

• G4AngularDistribution.hh
• G4AngularDistribution.cc