[u/mrichter/AliRoot.git] / PYTHIA6 / AliPythia.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */

#include "AliPythia.h"
#include "AliPythiaRndm.h"

ClassImp(AliPythia)

#ifndef WIN32
# define pyclus pyclus_
# define pycell pycell_
# define pyshow pyshow_
# define pyrobo pyrobo_
# define type_of_call
#else
# define pyclus PYCLUS
# define pycell PYCELL
# define pyrobo PYROBO
# define type_of_call _stdcall
#endif

extern "C" void type_of_call pyclus(Int_t & );
extern "C" void type_of_call pycell(Int_t & );
extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);

//_____________________________________________________________________________

AliPythia* AliPythia::fgAliPythia=NULL;

AliPythia::AliPythia()
{
// Default Constructor
//
//  Set random number
    if (!AliPythiaRndm::GetPythiaRandom()) 
      AliPythiaRndm::SetPythiaRandom(GetRandom());

}

void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
{
// Initialise the process to generate 
    if (!AliPythiaRndm::GetPythiaRandom()) 
      AliPythiaRndm::SetPythiaRandom(GetRandom());
    
    fProcess = process;
    fEcms = energy;
    fStrucFunc = strucfunc;
//  don't decay p0
    SetMDCY(Pycomp(111),1,0);
//  select structure function 
    SetMSTP(52,2);
    SetMSTP(51,strucfunc);
//
// Pythia initialisation for selected processes//
//
// Make MSEL clean
//
    for (Int_t i=1; i<= 200; i++) {
	SetMSUB(i,0);
    }
//  select charm production
    switch (process) 
    {
    case kPyCharm:
	SetMSEL(4);
//
//  heavy quark masses

	SetPMAS(4,1,1.2);
	SetMSTU(16,2);
//
//    primordial pT
	SetMSTP(91,1);
	SetPARP(91,1.);
	SetPARP(93,5.);
//
	break;
    case kPyBeauty:
	SetMSEL(5);
	SetPMAS(5,1,4.75);
	SetMSTU(16,2);
	break;
    case kPyJpsi:
	SetMSEL(0);
// gg->J/Psi g
	SetMSUB(86,1);
	break;
    case kPyJpsiChi:
	SetMSEL(0);
// gg->J/Psi g
	SetMSUB(86,1);
// gg-> chi_0c g
	SetMSUB(87,1);
// gg-> chi_1c g
	SetMSUB(88,1);
// gg-> chi_2c g
	SetMSUB(89,1);	
	break;
    case kPyCharmUnforced:
	SetMSEL(0);
// gq->qg   
	SetMSUB(28,1);
// gg->qq
	SetMSUB(53,1);
// gg->gg
	SetMSUB(68,1);
	break;
    case kPyBeautyUnforced:
	SetMSEL(0);
// gq->qg   
	SetMSUB(28,1);
// gg->qq
	SetMSUB(53,1);
// gg->gg
	SetMSUB(68,1);
	break;
    case kPyMb:
// Minimum Bias pp-Collisions
//
//   
//      select Pythia min. bias model
	SetMSEL(0);
	SetMSUB(92,1);      // single diffraction AB-->XB
	SetMSUB(93,1);      // single diffraction AB-->AX
	SetMSUB(94,1);      // double diffraction
	SetMSUB(95,1);	    // low pt production
	SetMSTP(81,1);      // multiple interactions switched on
	SetMSTP(82,3);      // model with varying impact param. & a single Gaussian
	SetPARP(82,3.47);   // set value pT_0  for turn-off of the cross section of                  
                            // multiple interaction at a reference energy = 14000 GeV
	SetPARP(89,14000.); // reference energy for the above parameter
	SetPARP(90,0.174);  // set exponent for energy dependence of pT_0
    case kPyMbNonDiffr:
// Minimum Bias pp-Collisions
//
//   
//      select Pythia min. bias model
	SetMSEL(0);
	SetMSUB(95,1);	    // low pt production
	SetMSTP(81,1);      // multiple interactions switched on
	SetMSTP(82,3);      // model with varying impact param. & a single Gaussian
	SetPARP(82,3.47);   // set value pT_0  for turn-off of the cross section of                  
                            // multiple interaction at a reference energy = 14000 GeV
	SetPARP(89,14000.); // reference energy for the above parameter
	SetPARP(90,0.174);  // set exponent for energy dependence of pT_0
 
	break;
    case kPyJets:
//
//  QCD Jets
//
	SetMSEL(1);
	break;
    case kPyDirectGamma:
	SetMSEL(10);
	break;
    case kPyCharmPbPbMNR:
    case kPyD0PbPbMNR:
      // Tuning of Pythia parameters aimed to get a resonable agreement
      // between with the NLO calculation by Mangano, Nason, Ridolfi for the
      // c-cbar single inclusive and double differential distributions.
      // This parameter settings are meant to work with Pb-Pb collisions
      // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
      // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
      // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.

      // All QCD processes
      SetMSEL(1);

      // No multiple interactions
      SetMSTP(81,0);
      SetPARP(81,0.0);
      SetPARP(82,0.0);

      // Initial/final parton shower on (Pythia default)
      SetMSTP(61,1);
      SetMSTP(71,1);

      // 2nd order alpha_s
      SetMSTP(2,2);

      // QCD scales
      SetMSTP(32,2);
      SetPARP(34,1.0);

      // Intrinsic <kT>
      SetMSTP(91,1);
      SetPARP(91,1.304);
      SetPARP(93,6.52);

      // Set c-quark mass
      SetPMAS(4,1,1.2);

      break;
    case kPyCharmpPbMNR:
    case kPyD0pPbMNR:
      // Tuning of Pythia parameters aimed to get a resonable agreement
      // between with the NLO calculation by Mangano, Nason, Ridolfi for the
      // c-cbar single inclusive and double differential distributions.
      // This parameter settings are meant to work with p-Pb collisions
      // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
      // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
      // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.

      // All QCD processes
      SetMSEL(1);

      // No multiple interactions
      SetMSTP(81,0);
      SetPARP(81,0.0);
      SetPARP(82,0.0);

      // Initial/final parton shower on (Pythia default)
      SetMSTP(61,1);
      SetMSTP(71,1);

      // 2nd order alpha_s
      SetMSTP(2,2);

      // QCD scales
      SetMSTP(32,2);
      SetPARP(34,1.0);

      // Intrinsic <kT>
      SetMSTP(91,1);
      SetPARP(91,1.16);
      SetPARP(93,5.8);

      // Set c-quark mass
      SetPMAS(4,1,1.2);

      break;
    case kPyCharmppMNR:
    case kPyD0ppMNR:
      // Tuning of Pythia parameters aimed to get a resonable agreement
      // between with the NLO calculation by Mangano, Nason, Ridolfi for the
      // c-cbar single inclusive and double differential distributions.
      // This parameter settings are meant to work with pp collisions
      // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
      // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
      // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.

      // All QCD processes
      SetMSEL(1);

      // No multiple interactions
      SetMSTP(81,0);
      SetPARP(81,0.0);
      SetPARP(82,0.0);

      // Initial/final parton shower on (Pythia default)
      SetMSTP(61,1);
      SetMSTP(71,1);

      // 2nd order alpha_s
      SetMSTP(2,2);

      // QCD scales
      SetMSTP(32,2);
      SetPARP(34,1.0);

      // Intrinsic <kT^2>
      SetMSTP(91,1);
      SetPARP(91,1.);
      SetPARP(93,5.);

      // Set c-quark mass
      SetPMAS(4,1,1.2);

      break;
    case kPyBeautyPbPbMNR:
      // Tuning of Pythia parameters aimed to get a resonable agreement
      // between with the NLO calculation by Mangano, Nason, Ridolfi for the
      // b-bbar single inclusive and double differential distributions.
      // This parameter settings are meant to work with Pb-Pb collisions
      // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
      // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
      // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.

      // All QCD processes
      SetMSEL(1);

      // No multiple interactions
      SetMSTP(81,0);
      SetPARP(81,0.0);
      SetPARP(82,0.0);

      // Initial/final parton shower on (Pythia default)
      SetMSTP(61,1);
      SetMSTP(71,1);

      // 2nd order alpha_s
      SetMSTP(2,2);

      // QCD scales
      SetMSTP(32,2);
      SetPARP(34,1.0);
      SetPARP(67,1.0);
      SetPARP(71,1.0);

      // Intrinsic <kT>
      SetMSTP(91,1);
      SetPARP(91,2.035);
      SetPARP(93,10.17);

      // Set b-quark mass
      SetPMAS(5,1,4.75);

      break;
    case kPyBeautypPbMNR:
      // Tuning of Pythia parameters aimed to get a resonable agreement
      // between with the NLO calculation by Mangano, Nason, Ridolfi for the
      // b-bbar single inclusive and double differential distributions.
      // This parameter settings are meant to work with p-Pb collisions
      // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
      // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
      // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.

      // All QCD processes
      SetMSEL(1);

      // No multiple interactions
      SetMSTP(81,0);
      SetPARP(81,0.0);
      SetPARP(82,0.0);

      // Initial/final parton shower on (Pythia default)
      SetMSTP(61,1);
      SetMSTP(71,1);

      // 2nd order alpha_s
      SetMSTP(2,2);

      // QCD scales
      SetMSTP(32,2);
      SetPARP(34,1.0);
      SetPARP(67,1.0);
      SetPARP(71,1.0);

      // Intrinsic <kT>
      SetMSTP(91,1);
      SetPARP(91,1.60);
      SetPARP(93,8.00);

      // Set b-quark mass
      SetPMAS(5,1,4.75);

      break;
    case kPyBeautyppMNR:
      // Tuning of Pythia parameters aimed to get a resonable agreement
      // between with the NLO calculation by Mangano, Nason, Ridolfi for the
      // b-bbar single inclusive and double differential distributions.
      // This parameter settings are meant to work with pp collisions
      // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
      // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
      // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.

      // All QCD processes
      SetMSEL(1);

      // No multiple interactions
      SetMSTP(81,0);
      SetPARP(81,0.0);
      SetPARP(82,0.0);

      // Initial/final parton shower on (Pythia default)
      SetMSTP(61,1);
      SetMSTP(71,1);

      // 2nd order alpha_s
      SetMSTP(2,2);

      // QCD scales
      SetMSTP(32,2);
      SetPARP(34,1.0);
      SetPARP(67,1.0);
      SetPARP(71,1.0);

      // Intrinsic <kT>
      SetMSTP(91,1);
      SetPARP(91,1.);
      SetPARP(93,5.);

      // Set b-quark mass
      SetPMAS(5,1,4.75);

      break;
    }
//
//  Initialize PYTHIA
    SetMSTP(41,1);   // all resonance decays switched on

    Initialize("CMS","p","p",fEcms);

}

Int_t AliPythia::CheckedLuComp(Int_t kf)
{
// Check Lund particle code (for debugging)
    Int_t kc=Pycomp(kf);
    printf("\n Lucomp kf,kc %d %d",kf,kc);
    return kc;
}

void AliPythia::SetNuclei(Int_t a1, Int_t a2)
{
// Treat protons as inside nuclei with mass numbers a1 and a2  
//    The MSTP array in the PYPARS common block is used to enable and 
//    select the nuclear structure functions. 
//    MSTP(52)  : (D=1) choice of proton and nuclear structure-function library
//            =1: internal PYTHIA acording to MSTP(51) 
//            =2: PDFLIB proton  s.f., with MSTP(51)  = 1000xNGROUP+NSET
//    If the following mass number both not equal zero, nuclear corrections of the stf are used.
//    MSTP(192) : Mass number of nucleus side 1
//    MSTP(193) : Mass number of nucleus side 2
    SetMSTP(52,2);
    SetMSTP(192, a1);
    SetMSTP(193, a2);  
}
	

AliPythia* AliPythia::Instance()
{ 
// Set random number generator 
    if (fgAliPythia) {
	return fgAliPythia;
    } else {
	fgAliPythia = new AliPythia();
	return fgAliPythia;
    }
}

void AliPythia::PrintParticles()
{ 
// Print list of particl properties
    Int_t np = 0;
    char*   name = new char[16];    
    for (Int_t kf=0; kf<1000000; kf++) {
	for (Int_t c = 1;  c > -2; c-=2) {
	    Int_t kc = Pycomp(c*kf);
	    if (kc) {
		Float_t mass  = GetPMAS(kc,1);
		Float_t width = GetPMAS(kc,2);	
		Float_t tau   = GetPMAS(kc,4);

		Pyname(kf,name);
	
		np++;
		
		printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e", 
		       c*kf, name, mass, width, tau);
	    }
	}
    }
    printf("\n Number of particles %d \n \n", np);
}

void  AliPythia::ResetDecayTable()
{
//  Set default values for pythia decay switches
    Int_t i;
    for (i = 1; i <  501; i++) SetMDCY(i,1,fDefMDCY[i]);
    for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
}

void  AliPythia::SetDecayTable()
{
//  Set default values for pythia decay switches
//
    Int_t i;
    for (i = 1; i <  501; i++) fDefMDCY[i] = GetMDCY(i,1);
    for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
}

void  AliPythia::Pyclus(Int_t& njet)
{
//  Call Pythia clustering algorithm
//
    pyclus(njet);
}

void  AliPythia::Pycell(Int_t& njet)
{
//  Call Pythia jet reconstruction algorithm
//
    pycell(njet);
}

void  AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
{
//  Call Pythia jet reconstruction algorithm
//
    Int_t numpart   = fPyjets->N;
    for (Int_t i = 0; i < numpart; i++)
    {
	if (fPyjets->K[2][i] == 7) ip1 = i+1;
	if (fPyjets->K[2][i] == 8) ip2 = i+1;
    }
    

    qmax = 2. * GetVINT(51);
    printf("Pyshow %d %d %f", ip1, ip2, qmax);
    
    pyshow(ip1, ip2, qmax);
}

void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
{
    pyrobo(imi, ima, the, phi, bex, bey, bez);
}


void  AliPythia::Quench()
{
//
//
//  Simple Jet Quenching routine:
//  =============================
//  The jet formed by all final state partons radiated by the parton created 
//  in the hard collisions is quenched by a factor z using:
//  (E + p_z)new = (1-z) (E + p_z)old
//
//   The lost momentum is first balanced by one gluon with virtuality > 0.   
//   Subsequently the gluon splits to yield two gluons with E = p.
//
    Float_t p0[2][5];
    Float_t p1[2][5];
    Float_t p2[2][5];
    Int_t   klast[2] = {-1, -1};
    Int_t   kglu[2];
    for (Int_t i = 0; i < 4; i++)
    {
	p0[0][i] = 0.;
	p0[1][i] = 0.;
	p1[0][i] = 0.;
	p1[1][i] = 0.;
	p2[0][i] = 0.;
	p2[1][i] = 0.;
    }

    Int_t numpart   = fPyjets->N;

    for (Int_t i = 0; i < numpart; i++)
    {
	Int_t imo =  fPyjets->K[2][i];
	Int_t kst =  fPyjets->K[0][i];
	Int_t pdg =  fPyjets->K[1][i];
	
//      Quarks and gluons only
	if (pdg != 21 && TMath::Abs(pdg) > 6) continue;

//      Particles from hard scattering only


	Float_t px = fPyjets->P[0][i];
	Float_t py = fPyjets->P[1][i];
	Float_t pz = fPyjets->P[2][i];
	Float_t e  = fPyjets->P[3][i];
	Float_t m  = fPyjets->P[4][i];
	Float_t pt = TMath::Sqrt(px * px + py * py);
//      Skip comment lines
	if (kst != 1 && kst != 2) continue;

	Float_t mt = TMath::Sqrt(px * px + py * py + m * m);

	//
	// Some cuts to be in a save kinematic region
	//
	if (imo != 7 && imo != 8) continue;
	Int_t index = imo - 7;
	klast[index] = i;
	
	p0[index][0] += px;
	p0[index][1] += py;
	p0[index][2] += pz;
	p0[index][3] += e;	
	
	//
	// Fix z
	//

	Float_t z       = 0.2;
	Float_t eppzOld = e + pz;
	Float_t empzOld = e - pz;


	//
	// Kinematics of the original parton
	// 

	Float_t eppzNew = (1. - z) * eppzOld;
	Float_t empzNew = empzOld - mt * mt * z / eppzOld;
	Float_t eNew0    = 0.5 * (eppzNew + empzNew);
	Float_t pzNew0   = 0.5 * (eppzNew - empzNew);
	//
        // Skip if pt too small
	// 
	if (m * m > eppzNew * empzNew) continue;
	Float_t ptNew    = TMath::Sqrt(eppzNew * empzNew - m * m);
	Float_t pxNew0   = ptNew / pt * px;
	Float_t pyNew0   = ptNew / pt * py;	

	p1[index][0] += pxNew0;
	p1[index][1] += pyNew0;
	p1[index][2] += pzNew0;
	p1[index][3] += eNew0;	
	//
	// Update event record
	//
	fPyjets->P[0][i] = pxNew0;
	fPyjets->P[1][i] = pyNew0;
	fPyjets->P[2][i] = pzNew0;
	fPyjets->P[3][i] = eNew0;
	
    }

    //
    // Gluons
    // 
    
    for (Int_t k = 0; k < 2; k++) 
    {
	for (Int_t j = 0; j < 4; j++) 
	{
	    p2[k][j] = p0[k][j] - p1[k][j];
	}
	p2[k][4] = p2[k][3] * p2[k][3] - p2[k][0] * p2[k][0] - p2[k][1] * p2[k][1] - p2[k][2] * p2[k][2];

	if (p2[k][4] > 0.)
	{

	    //
	    // Bring gluon back to mass shell via momentum scaling 
	    // (momentum will not be conserved, but energy)
	    //
	    // not used anymore
/*
	    Float_t psq   = p2[k][0] * p2[k][0] + p2[k][1] * p2[k][1] + p2[k][2] * p2[k][2];
	    Float_t fact  = TMath::Sqrt(1. + p2[k][4] / psq);
	    p2[k][0] *= fact;
	    p2[k][1] *= fact;
	    p2[k][2] *= fact;
	    p2[k][3]  = TMath::Sqrt(psq) * fact;
	    p2[k][4]  = 0.;
*/
	}
    }

    if (p2[0][4] > 0.) {
	p2[0][4] = TMath::Sqrt(p2[0][4]);
    } else {
	printf("Warning negative mass squared ! \n");
    }
    
    if (p2[1][4] > 0.) {
	p2[1][4] = TMath::Sqrt(p2[1][4]);
    } else {
	printf("Warning negative mass squared ! \n");
    }
    
    //
    // Add the gluons
    //
    
    
    for (Int_t i = 0; i < 2; i++) {
	Int_t ish, jmin, jmax, iGlu, iNew;
	Int_t in = klast[i];
	ish = 0;
	
	if (in == -1) continue;
	if (i == 1 && klast[1] > klast[0]) in += ish;
	
	jmin = in - 1;
	ish  = 1;

	if (p2[i][4] > 0) ish = 2;
	
	iGlu = in;
	iNew = in + ish;
	jmax = numpart + ish - 1;
 
	if (fPyjets->K[0][in-1] == 1 || fPyjets->K[0][in-1] == 21 || fPyjets->K[0][in-1] == 11) {
	    jmin = in;
	    iGlu = in + 1;
	    iNew = in;
	}

	kglu[i] = iGlu;
	
	for (Int_t j = jmax; j > jmin; j--)
	{
	    for (Int_t k = 0; k < 5; k++) {
		fPyjets->K[k][j] =  fPyjets->K[k][j-ish];
		fPyjets->P[k][j] =  fPyjets->P[k][j-ish];
		fPyjets->V[k][j] =  fPyjets->V[k][j-ish];
	    }
	} // end shifting
	numpart += ish;
	(fPyjets->N) += ish;
	
	if (ish == 1) {
	    fPyjets->P[0][iGlu] = p2[i][0];
	    fPyjets->P[1][iGlu] = p2[i][1];
	    fPyjets->P[2][iGlu] = p2[i][2];
	    fPyjets->P[3][iGlu] = p2[i][3];
	    fPyjets->P[4][iGlu] = p2[i][4];
	    
	    fPyjets->K[0][iGlu] = 2;
	    fPyjets->K[1][iGlu] = 21;	
	    fPyjets->K[2][iGlu] = fPyjets->K[2][iNew];
	    fPyjets->K[3][iGlu] = -1;	
	    fPyjets->K[4][iGlu] = -1;
	} else {
	    //
	    // Split gluon in rest frame.
	    //
	    Double_t bx =  p2[i][0] / p2[i][3];
	    Double_t by =  p2[i][1] / p2[i][3];
	    Double_t bz =  p2[i][2] / p2[i][3];
	    
	    Float_t pst  = p2[i][4] / 2.;
	    
	    Float_t cost = 2. * gRandom->Rndm() - 1.;
	    Float_t sint = TMath::Sqrt(1. - cost * cost);
	    Float_t phi = 2. * TMath::Pi() * gRandom->Rndm();
	    
	    Float_t pz1 =   pst * cost;
	    Float_t pz2 =  -pst * cost;
	    Float_t pt1 =   pst * sint;
	    Float_t pt2 =  -pst * sint;
	    Float_t px1 =   pt1 * TMath::Cos(phi);
	    Float_t py1 =   pt1 * TMath::Sin(phi);	    
	    Float_t px2 =   pt2 * TMath::Cos(phi);
	    Float_t py2 =   pt2 * TMath::Sin(phi);	    
	    
	    fPyjets->P[0][iGlu] = px1;
	    fPyjets->P[1][iGlu] = py1;
	    fPyjets->P[2][iGlu] = pz1;
	    fPyjets->P[3][iGlu] = pst;
	    fPyjets->P[4][iGlu] = 0.;
	    
	    fPyjets->K[0][iGlu] = 2;
	    fPyjets->K[1][iGlu] = 21;	
	    fPyjets->K[2][iGlu] = fPyjets->K[2][iNew];
	    fPyjets->K[3][iGlu] = -1;	
	    fPyjets->K[4][iGlu] = -1;

	    fPyjets->P[0][iGlu+1] = px2;
	    fPyjets->P[1][iGlu+1] = py2;
	    fPyjets->P[2][iGlu+1] = pz2;
	    fPyjets->P[3][iGlu+1] = pst;
	    fPyjets->P[4][iGlu+1] = 0.;
	    
	    fPyjets->K[0][iGlu+1] = 2;
	    fPyjets->K[1][iGlu+1] = 21;	
	    fPyjets->K[2][iGlu+1] = fPyjets->K[2][iNew];
	    fPyjets->K[3][iGlu+1] = -1;	
	    fPyjets->K[4][iGlu+1] = -1;
	    SetMSTU(1,0);
	    SetMSTU(2,0);

	    //
	    // Boost back
	    //
	    Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);

	}
    } // end adding gluons
} // end quench
Commit	Line	Data
8d2cd130	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
7cdba479	16	/* $Id$ */
8d2cd130	17
8d2cd130	18	#include "AliPythia.h"
7cdba479	19	#include "AliPythiaRndm.h"
8d2cd130	20
	21	ClassImp(AliPythia)
	22
	23	#ifndef WIN32
	24	# define pyclus pyclus_
	25	# define pycell pycell_
452af8c7	26	# define pyshow pyshow_
452af8c7	27	# define pyrobo pyrobo_
8d2cd130	28	# define type_of_call
	29	#else
	30	# define pyclus PYCLUS
	31	# define pycell PYCELL
452af8c7	32	# define pyrobo PYROBO
8d2cd130	33	# define type_of_call _stdcall
	34	#endif
	35
	36	extern "C" void type_of_call pyclus(Int_t & );
	37	extern "C" void type_of_call pycell(Int_t & );
452af8c7	38	extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
452af8c7	39	extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
8d2cd130	40
	41	//_____________________________________________________________________________
	42
	43	AliPythia* AliPythia::fgAliPythia=NULL;
	44
	45	AliPythia::AliPythia()
	46	{
	47	// Default Constructor
	48	//
	49	// Set random number
7cdba479	50	if (!AliPythiaRndm::GetPythiaRandom())
7cdba479	51	AliPythiaRndm::SetPythiaRandom(GetRandom());
8d2cd130	52
	53	}
	54
	55	void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
	56	{
	57	// Initialise the process to generate
7cdba479	58	if (!AliPythiaRndm::GetPythiaRandom())
7cdba479	59	AliPythiaRndm::SetPythiaRandom(GetRandom());
8d2cd130	60
	61	fProcess = process;
	62	fEcms = energy;
	63	fStrucFunc = strucfunc;
	64	// don't decay p0
	65	SetMDCY(Pycomp(111),1,0);
	66	// select structure function
	67	SetMSTP(52,2);
	68	SetMSTP(51,strucfunc);
	69	//
	70	// Pythia initialisation for selected processes//
	71	//
	72	// Make MSEL clean
	73	//
	74	for (Int_t i=1; i<= 200; i++) {
	75	SetMSUB(i,0);
	76	}
	77	// select charm production
	78	switch (process)
	79	{
	80	case kPyCharm:
	81	SetMSEL(4);
	82	//
	83	// heavy quark masses
	84
	85	SetPMAS(4,1,1.2);
	86	SetMSTU(16,2);
	87	//
	88	// primordial pT
	89	SetMSTP(91,1);
	90	SetPARP(91,1.);
	91	SetPARP(93,5.);
	92	//
	93	break;
	94	case kPyBeauty:
	95	SetMSEL(5);
	96	SetPMAS(5,1,4.75);
	97	SetMSTU(16,2);
	98	break;
	99	case kPyJpsi:
	100	SetMSEL(0);
	101	// gg->J/Psi g
	102	SetMSUB(86,1);
	103	break;
	104	case kPyJpsiChi:
	105	SetMSEL(0);
	106	// gg->J/Psi g
	107	SetMSUB(86,1);
	108	// gg-> chi_0c g
	109	SetMSUB(87,1);
	110	// gg-> chi_1c g
	111	SetMSUB(88,1);
	112	// gg-> chi_2c g
	113	SetMSUB(89,1);
	114	break;
	115	case kPyCharmUnforced:
	116	SetMSEL(0);
	117	// gq->qg
	118	SetMSUB(28,1);
	119	// gg->qq
	120	SetMSUB(53,1);
	121	// gg->gg
	122	SetMSUB(68,1);
	123	break;
124	case kPyBeautyUnforced:
125	SetMSEL(0);
126	// gq->qg
127	SetMSUB(28,1);
128	// gg->qq
129	SetMSUB(53,1);
130	// gg->gg
131	SetMSUB(68,1);
132	break;
133	case kPyMb:
134	// Minimum Bias pp-Collisions
135	//
136	//
137	// select Pythia min. bias model
138	SetMSEL(0);
139	SetMSUB(92,1); // single diffraction AB-->XB
140	SetMSUB(93,1); // single diffraction AB-->AX
141	SetMSUB(94,1); // double diffraction
142	SetMSUB(95,1); // low pt production
143	SetMSTP(81,1); // multiple interactions switched on
144	SetMSTP(82,3); // model with varying impact param. & a single Gaussian
145	SetPARP(82,3.47); // set value pT_0 for turn-off of the cross section of
146	// multiple interaction at a reference energy = 14000 GeV
147	SetPARP(89,14000.); // reference energy for the above parameter
148	SetPARP(90,0.174); // set exponent for energy dependence of pT_0
149	case kPyMbNonDiffr:
150	// Minimum Bias pp-Collisions
151	//
152	//
153	// select Pythia min. bias model
154	SetMSEL(0);
155	SetMSUB(95,1); // low pt production
156	SetMSTP(81,1); // multiple interactions switched on
157	SetMSTP(82,3); // model with varying impact param. & a single Gaussian
158	SetPARP(82,3.47); // set value pT_0 for turn-off of the cross section of
159	// multiple interaction at a reference energy = 14000 GeV
160	SetPARP(89,14000.); // reference energy for the above parameter
161	SetPARP(90,0.174); // set exponent for energy dependence of pT_0
162
163	break;
164	case kPyJets:
165	//
166	// QCD Jets
167	//
168	SetMSEL(1);
169	break;
170	case kPyDirectGamma:
171	SetMSEL(10);
172	break;
adf4d898	173	case kPyCharmPbPbMNR:
adf4d898	174	case kPyD0PbPbMNR:
8d2cd130	175	// Tuning of Pythia parameters aimed to get a resonable agreement
	176	// between with the NLO calculation by Mangano, Nason, Ridolfi for the
	177	// c-cbar single inclusive and double differential distributions.
	178	// This parameter settings are meant to work with Pb-Pb collisions
adf4d898	179	// (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
8d2cd130	180	// To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
	181	// has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
	182
	183	// All QCD processes
	184	SetMSEL(1);
	185
	186	// No multiple interactions
	187	SetMSTP(81,0);
	188	SetPARP(81,0.0);
	189	SetPARP(82,0.0);
	190
	191	// Initial/final parton shower on (Pythia default)
	192	SetMSTP(61,1);
	193	SetMSTP(71,1);
	194
	195	// 2nd order alpha_s
	196	SetMSTP(2,2);
	197
	198	// QCD scales
	199	SetMSTP(32,2);
	200	SetPARP(34,1.0);
	201
adf4d898	202	// Intrinsic <kT>
8d2cd130	203	SetMSTP(91,1);
	204	SetPARP(91,1.304);
	205	SetPARP(93,6.52);
	206
	207	// Set c-quark mass
	208	SetPMAS(4,1,1.2);
	209
	210	break;
adf4d898	211	case kPyCharmpPbMNR:
	212	case kPyD0pPbMNR:
	213	// Tuning of Pythia parameters aimed to get a resonable agreement
	214	// between with the NLO calculation by Mangano, Nason, Ridolfi for the
	215	// c-cbar single inclusive and double differential distributions.
	216	// This parameter settings are meant to work with p-Pb collisions
	217	// (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
	218	// To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
	219	// has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
	220
	221	// All QCD processes
	222	SetMSEL(1);
	223
	224	// No multiple interactions
	225	SetMSTP(81,0);
	226	SetPARP(81,0.0);
	227	SetPARP(82,0.0);
	228
	229	// Initial/final parton shower on (Pythia default)
	230	SetMSTP(61,1);
	231	SetMSTP(71,1);
	232
	233	// 2nd order alpha_s
	234	SetMSTP(2,2);
	235
	236	// QCD scales
	237	SetMSTP(32,2);
	238	SetPARP(34,1.0);
	239
	240	// Intrinsic <kT>
	241	SetMSTP(91,1);
	242	SetPARP(91,1.16);
	243	SetPARP(93,5.8);
	244
	245	// Set c-quark mass
	246	SetPMAS(4,1,1.2);
	247
	248	break;
	249	case kPyCharmppMNR:
	250	case kPyD0ppMNR:
	251	// Tuning of Pythia parameters aimed to get a resonable agreement
	252	// between with the NLO calculation by Mangano, Nason, Ridolfi for the
	253	// c-cbar single inclusive and double differential distributions.
	254	// This parameter settings are meant to work with pp collisions
	255	// (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
	256	// To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
	257	// has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
	258
	259	// All QCD processes
	260	SetMSEL(1);
	261
	262	// No multiple interactions
	263	SetMSTP(81,0);
	264	SetPARP(81,0.0);
	265	SetPARP(82,0.0);
	266
	267	// Initial/final parton shower on (Pythia default)
	268	SetMSTP(61,1);
	269	SetMSTP(71,1);
	270
	271	// 2nd order alpha_s
	272	SetMSTP(2,2);
	273
	274	// QCD scales
275	SetMSTP(32,2);
276	SetPARP(34,1.0);
277
278	// Intrinsic <kT^2>
279	SetMSTP(91,1);
280	SetPARP(91,1.);
281	SetPARP(93,5.);
282
283	// Set c-quark mass
284	SetPMAS(4,1,1.2);
285
286	break;
287	case kPyBeautyPbPbMNR:
8d2cd130	288	// Tuning of Pythia parameters aimed to get a resonable agreement
	289	// between with the NLO calculation by Mangano, Nason, Ridolfi for the
	290	// b-bbar single inclusive and double differential distributions.
	291	// This parameter settings are meant to work with Pb-Pb collisions
	292	// (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
	293	// To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
	294	// has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
	295
	296	// All QCD processes
	297	SetMSEL(1);
	298
	299	// No multiple interactions
	300	SetMSTP(81,0);
	301	SetPARP(81,0.0);
	302	SetPARP(82,0.0);
	303
	304	// Initial/final parton shower on (Pythia default)
	305	SetMSTP(61,1);
	306	SetMSTP(71,1);
	307
	308	// 2nd order alpha_s
	309	SetMSTP(2,2);
	310
	311	// QCD scales
	312	SetMSTP(32,2);
	313	SetPARP(34,1.0);
	314	SetPARP(67,1.0);
	315	SetPARP(71,1.0);
	316
adf4d898	317	// Intrinsic <kT>
8d2cd130	318	SetMSTP(91,1);
	319	SetPARP(91,2.035);
	320	SetPARP(93,10.17);
	321
	322	// Set b-quark mass
	323	SetPMAS(5,1,4.75);
	324
adf4d898	325	break;
	326	case kPyBeautypPbMNR:
	327	// Tuning of Pythia parameters aimed to get a resonable agreement
	328	// between with the NLO calculation by Mangano, Nason, Ridolfi for the
	329	// b-bbar single inclusive and double differential distributions.
	330	// This parameter settings are meant to work with p-Pb collisions
	331	// (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
	332	// To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
	333	// has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
	334
	335	// All QCD processes
	336	SetMSEL(1);
	337
	338	// No multiple interactions
	339	SetMSTP(81,0);
	340	SetPARP(81,0.0);
	341	SetPARP(82,0.0);
	342
	343	// Initial/final parton shower on (Pythia default)
	344	SetMSTP(61,1);
	345	SetMSTP(71,1);
	346
	347	// 2nd order alpha_s
	348	SetMSTP(2,2);
	349
	350	// QCD scales
	351	SetMSTP(32,2);
	352	SetPARP(34,1.0);
	353	SetPARP(67,1.0);
	354	SetPARP(71,1.0);
	355
	356	// Intrinsic <kT>
	357	SetMSTP(91,1);
	358	SetPARP(91,1.60);
	359	SetPARP(93,8.00);
	360
	361	// Set b-quark mass
	362	SetPMAS(5,1,4.75);
	363
	364	break;
	365	case kPyBeautyppMNR:
	366	// Tuning of Pythia parameters aimed to get a resonable agreement
	367	// between with the NLO calculation by Mangano, Nason, Ridolfi for the
	368	// b-bbar single inclusive and double differential distributions.
	369	// This parameter settings are meant to work with pp collisions
	370	// (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
	371	// To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
	372	// has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
	373
	374	// All QCD processes
	375	SetMSEL(1);
	376
	377	// No multiple interactions
	378	SetMSTP(81,0);
	379	SetPARP(81,0.0);
	380	SetPARP(82,0.0);
	381
	382	// Initial/final parton shower on (Pythia default)
	383	SetMSTP(61,1);
	384	SetMSTP(71,1);
	385
	386	// 2nd order alpha_s
	387	SetMSTP(2,2);
	388
389	// QCD scales
390	SetMSTP(32,2);
391	SetPARP(34,1.0);
392	SetPARP(67,1.0);
393	SetPARP(71,1.0);
394
395	// Intrinsic <kT>
396	SetMSTP(91,1);
397	SetPARP(91,1.);
398	SetPARP(93,5.);
399
400	// Set b-quark mass
401	SetPMAS(5,1,4.75);
402
8d2cd130	403	break;
	404	}
	405	//
	406	// Initialize PYTHIA
	407	SetMSTP(41,1); // all resonance decays switched on
	408
	409	Initialize("CMS","p","p",fEcms);
	410
	411	}
	412
	413	Int_t AliPythia::CheckedLuComp(Int_t kf)
	414	{
	415	// Check Lund particle code (for debugging)
	416	Int_t kc=Pycomp(kf);
	417	printf("\n Lucomp kf,kc %d %d",kf,kc);
	418	return kc;
	419	}
	420
	421	void AliPythia::SetNuclei(Int_t a1, Int_t a2)
	422	{
	423	// Treat protons as inside nuclei with mass numbers a1 and a2
	424	// The MSTP array in the PYPARS common block is used to enable and
	425	// select the nuclear structure functions.
	426	// MSTP(52) : (D=1) choice of proton and nuclear structure-function library
	427	// =1: internal PYTHIA acording to MSTP(51)
	428	// =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
	429	// If the following mass number both not equal zero, nuclear corrections of the stf are used.
	430	// MSTP(192) : Mass number of nucleus side 1
	431	// MSTP(193) : Mass number of nucleus side 2
	432	SetMSTP(52,2);
	433	SetMSTP(192, a1);
	434	SetMSTP(193, a2);
	435	}
	436
	437
	438	AliPythia* AliPythia::Instance()
	439	{
	440	// Set random number generator
	441	if (fgAliPythia) {
	442	return fgAliPythia;
	443	} else {
	444	fgAliPythia = new AliPythia();
	445	return fgAliPythia;
	446	}
	447	}
	448
	449	void AliPythia::PrintParticles()
	450	{
	451	// Print list of particl properties
	452	Int_t np = 0;
c31f1d37	453	char* name = new char[16];
8d2cd130	454	for (Int_t kf=0; kf<1000000; kf++) {
8d2cd130	455	for (Int_t c = 1; c > -2; c-=2) {
8d2cd130	456	Int_t kc = Pycomp(c*kf);
	457	if (kc) {
	458	Float_t mass = GetPMAS(kc,1);
	459	Float_t width = GetPMAS(kc,2);
	460	Float_t tau = GetPMAS(kc,4);
c31f1d37	461
8d2cd130	462	Pyname(kf,name);
	463
	464	np++;
	465
	466	printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
	467	c*kf, name, mass, width, tau);
	468	}
	469	}
	470	}
	471	printf("\n Number of particles %d \n \n", np);
	472	}
	473
	474	void AliPythia::ResetDecayTable()
	475	{
	476	// Set default values for pythia decay switches
	477	Int_t i;
	478	for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
	479	for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
	480	}
	481
	482	void AliPythia::SetDecayTable()
	483	{
	484	// Set default values for pythia decay switches
	485	//
	486	Int_t i;
	487	for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
	488	for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
	489	}
	490
	491	void AliPythia::Pyclus(Int_t& njet)
	492	{
	493	// Call Pythia clustering algorithm
	494	//
	495	pyclus(njet);
	496	}
	497
	498	void AliPythia::Pycell(Int_t& njet)
	499	{
	500	// Call Pythia jet reconstruction algorithm
	501	//
	502	pycell(njet);
	503	}
	504
452af8c7	505	void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
	506	{
	507	// Call Pythia jet reconstruction algorithm
	508	//
	509	Int_t numpart = fPyjets->N;
	510	for (Int_t i = 0; i < numpart; i++)
	511	{
	512	if (fPyjets->K[2][i] == 7) ip1 = i+1;
	513	if (fPyjets->K[2][i] == 8) ip2 = i+1;
	514	}
	515
	516
	517	qmax = 2. * GetVINT(51);
	518	printf("Pyshow %d %d %f", ip1, ip2, qmax);
	519
	520	pyshow(ip1, ip2, qmax);
	521	}
	522
	523	void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
	524	{
	525	pyrobo(imi, ima, the, phi, bex, bey, bez);
	526	}
	527
	528
	529
	530	void AliPythia::Quench()
	531	{
	532	//
	533	//
	534	// Simple Jet Quenching routine:
	535	// =============================
	536	// The jet formed by all final state partons radiated by the parton created
	537	// in the hard collisions is quenched by a factor z using:
	538	// (E + p_z)new = (1-z) (E + p_z)old
	539	//
	540	// The lost momentum is first balanced by one gluon with virtuality > 0.
	541	// Subsequently the gluon splits to yield two gluons with E = p.
	542	//
	543	Float_t p0[2][5];
	544	Float_t p1[2][5];
	545	Float_t p2[2][5];
	546	Int_t klast[2] = {-1, -1};
	547	Int_t kglu[2];
	548	for (Int_t i = 0; i < 4; i++)
	549	{
	550	p0[0][i] = 0.;
	551	p0[1][i] = 0.;
	552	p1[0][i] = 0.;
	553	p1[1][i] = 0.;
	554	p2[0][i] = 0.;
	555	p2[1][i] = 0.;
	556	}
	557
	558	Int_t numpart = fPyjets->N;
	559
	560	for (Int_t i = 0; i < numpart; i++)
	561	{
	562	Int_t imo = fPyjets->K[2][i];
	563	Int_t kst = fPyjets->K[0][i];
	564	Int_t pdg = fPyjets->K[1][i];
	565
	566	// Quarks and gluons only
	567	if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
	568
569	// Particles from hard scattering only
570
571
572	Float_t px = fPyjets->P[0][i];
573	Float_t py = fPyjets->P[1][i];
574	Float_t pz = fPyjets->P[2][i];
575	Float_t e = fPyjets->P[3][i];
576	Float_t m = fPyjets->P[4][i];
577	Float_t pt = TMath::Sqrt(px * px + py * py);
578	// Skip comment lines
579	if (kst != 1 && kst != 2) continue;
580
581	Float_t mt = TMath::Sqrt(px * px + py * py + m * m);
582
583	//
584	// Some cuts to be in a save kinematic region
585	//
586	if (imo != 7 && imo != 8) continue;
587	Int_t index = imo - 7;
588	klast[index] = i;
589
590	p0[index][0] += px;
591	p0[index][1] += py;
592	p0[index][2] += pz;
593	p0[index][3] += e;
594
595	//
596	// Fix z
597	//
598
599	Float_t z = 0.2;
600	Float_t eppzOld = e + pz;
601	Float_t empzOld = e - pz;
602
603
604	//
605	// Kinematics of the original parton
606	//
607
608	Float_t eppzNew = (1. - z) * eppzOld;
609	Float_t empzNew = empzOld - mt * mt * z / eppzOld;
610	Float_t eNew0 = 0.5 * (eppzNew + empzNew);
611	Float_t pzNew0 = 0.5 * (eppzNew - empzNew);
612	//
613	// Skip if pt too small
614	//
615	if (m * m > eppzNew * empzNew) continue;
616	Float_t ptNew = TMath::Sqrt(eppzNew * empzNew - m * m);
617	Float_t pxNew0 = ptNew / pt * px;
618	Float_t pyNew0 = ptNew / pt * py;
619
620	p1[index][0] += pxNew0;
621	p1[index][1] += pyNew0;
622	p1[index][2] += pzNew0;
623	p1[index][3] += eNew0;
624	//
625	// Update event record
626	//
627	fPyjets->P[0][i] = pxNew0;
628	fPyjets->P[1][i] = pyNew0;
629	fPyjets->P[2][i] = pzNew0;
630	fPyjets->P[3][i] = eNew0;
631
632	}
633
634	//
635	// Gluons
636	//
637
638	for (Int_t k = 0; k < 2; k++)
639	{
640	for (Int_t j = 0; j < 4; j++)
641	{
642	p2[k][j] = p0[k][j] - p1[k][j];
643	}
644	p2[k][4] = p2[k][3] * p2[k][3] - p2[k][0] * p2[k][0] - p2[k][1] * p2[k][1] - p2[k][2] * p2[k][2];
645
646	if (p2[k][4] > 0.)
647	{
648
649	//
650	// Bring gluon back to mass shell via momentum scaling
651	// (momentum will not be conserved, but energy)
652	//
653	// not used anymore
654	/*
655	Float_t psq = p2[k][0] * p2[k][0] + p2[k][1] * p2[k][1] + p2[k][2] * p2[k][2];
656	Float_t fact = TMath::Sqrt(1. + p2[k][4] / psq);
657	p2[k][0] *= fact;
658	p2[k][1] *= fact;
659	p2[k][2] *= fact;
660	p2[k][3] = TMath::Sqrt(psq) * fact;
661	p2[k][4] = 0.;
662	*/
663	}
664	}
665
666	if (p2[0][4] > 0.) {
667	p2[0][4] = TMath::Sqrt(p2[0][4]);
668	} else {
669	printf("Warning negative mass squared ! \n");
670	}
671
672	if (p2[1][4] > 0.) {
673	p2[1][4] = TMath::Sqrt(p2[1][4]);
674	} else {
675	printf("Warning negative mass squared ! \n");
676	}
677
678	//
679	// Add the gluons
680	//
681
682
683	for (Int_t i = 0; i < 2; i++) {
684	Int_t ish, jmin, jmax, iGlu, iNew;
685	Int_t in = klast[i];
686	ish = 0;
687
688	if (in == -1) continue;
689	if (i == 1 && klast[1] > klast[0]) in += ish;
690
691	jmin = in - 1;
692	ish = 1;
693
694	if (p2[i][4] > 0) ish = 2;
695
696	iGlu = in;
697	iNew = in + ish;
698	jmax = numpart + ish - 1;
699
700	if (fPyjets->K[0][in-1] == 1 \|\| fPyjets->K[0][in-1] == 21 \|\| fPyjets->K[0][in-1] == 11) {
701	jmin = in;
702	iGlu = in + 1;
703	iNew = in;
704	}
705
706	kglu[i] = iGlu;
707
708	for (Int_t j = jmax; j > jmin; j--)
709	{
710	for (Int_t k = 0; k < 5; k++) {
711	fPyjets->K[k][j] = fPyjets->K[k][j-ish];
712	fPyjets->P[k][j] = fPyjets->P[k][j-ish];
713	fPyjets->V[k][j] = fPyjets->V[k][j-ish];
714	}
715	} // end shifting
716	numpart += ish;
717	(fPyjets->N) += ish;
718
719	if (ish == 1) {
720	fPyjets->P[0][iGlu] = p2[i][0];
721	fPyjets->P[1][iGlu] = p2[i][1];
722	fPyjets->P[2][iGlu] = p2[i][2];
723	fPyjets->P[3][iGlu] = p2[i][3];
724	fPyjets->P[4][iGlu] = p2[i][4];
725
726	fPyjets->K[0][iGlu] = 2;
727	fPyjets->K[1][iGlu] = 21;
728	fPyjets->K[2][iGlu] = fPyjets->K[2][iNew];
729	fPyjets->K[3][iGlu] = -1;
730	fPyjets->K[4][iGlu] = -1;
731	} else {
732	//
733	// Split gluon in rest frame.
734	//
735	Double_t bx = p2[i][0] / p2[i][3];
736	Double_t by = p2[i][1] / p2[i][3];
737	Double_t bz = p2[i][2] / p2[i][3];
738
739	Float_t pst = p2[i][4] / 2.;
740
741	Float_t cost = 2. * gRandom->Rndm() - 1.;
742	Float_t sint = TMath::Sqrt(1. - cost * cost);
743	Float_t phi = 2. * TMath::Pi() * gRandom->Rndm();
744
745	Float_t pz1 = pst * cost;
746	Float_t pz2 = -pst * cost;
747	Float_t pt1 = pst * sint;
748	Float_t pt2 = -pst * sint;
749	Float_t px1 = pt1 * TMath::Cos(phi);
750	Float_t py1 = pt1 * TMath::Sin(phi);
751	Float_t px2 = pt2 * TMath::Cos(phi);
752	Float_t py2 = pt2 * TMath::Sin(phi);
753
754	fPyjets->P[0][iGlu] = px1;
755	fPyjets->P[1][iGlu] = py1;
756	fPyjets->P[2][iGlu] = pz1;
757	fPyjets->P[3][iGlu] = pst;
758	fPyjets->P[4][iGlu] = 0.;
759
760	fPyjets->K[0][iGlu] = 2;
761	fPyjets->K[1][iGlu] = 21;
762	fPyjets->K[2][iGlu] = fPyjets->K[2][iNew];
763	fPyjets->K[3][iGlu] = -1;
764	fPyjets->K[4][iGlu] = -1;
765
766	fPyjets->P[0][iGlu+1] = px2;
767	fPyjets->P[1][iGlu+1] = py2;
768	fPyjets->P[2][iGlu+1] = pz2;
769	fPyjets->P[3][iGlu+1] = pst;
770	fPyjets->P[4][iGlu+1] = 0.;
771
772	fPyjets->K[0][iGlu+1] = 2;
773	fPyjets->K[1][iGlu+1] = 21;
774	fPyjets->K[2][iGlu+1] = fPyjets->K[2][iNew];
775	fPyjets->K[3][iGlu+1] = -1;
776	fPyjets->K[4][iGlu+1] = -1;
777	SetMSTU(1,0);
778	SetMSTU(2,0);
779
780	//
781	// Boost back
782	//
783	Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
784
785	}
786	} // end adding gluons
787	} // end quench
788
789