[u/mrichter/AliRoot.git] / PYTHIA8 / pythia8145 / include / BoseEinstein.h

// Bose-Einstein.h is a part of the PYTHIA event generator.
// Copyright (C) 2010 Torbjorn Sjostrand.
// PYTHIA is licenced under the GNU GPL version 2, see COPYING for details.
// Please respect the MCnet Guidelines, see GUIDELINES for details.

// This file contains the classes to handle Bose-Einstein effects.
// BoseEinsteinHadron: simple working container for particle momenta.
// BoseEinstein: main class to perform the task.

#ifndef Pythia8_BoseEinstein_H
#define Pythia8_BoseEinstein_H

#include "Basics.h"
#include "Event.h"
#include "ParticleData.h"
#include "PythiaStdlib.h"
#include "Settings.h"

namespace Pythia8 {
 
//==========================================================================
 
// The BoseEinsteinHadron class is a simple container for studied hadrons.

class BoseEinsteinHadron {

public:

  // Constructors. 
  BoseEinsteinHadron() : id(0), iPos(0), p(0.), pShift(0.), pComp(0.), 
    m2(0.) {}
  BoseEinsteinHadron(int idIn,  int iPosIn, Vec4 pIn, double mIn) : 
    id(idIn), iPos(iPosIn), p(pIn), pShift(0.), pComp(0.) {m2 = mIn*mIn;}

  // Information on hadron - all public.
  int    id, iPos;
  Vec4   p, pShift, pComp;
  double m2;

};

//==========================================================================

// The BoseEinstein class shifts the momenta of identical particles relative 
// to each other, to simulate Bose-Einstein effects to some approximation.

class BoseEinstein {

public:

  // Constructor. 
  BoseEinstein() {}

  // Find settings. Precalculate table used to find momentum shifts.
  bool init(Info* infoPtrIn, Settings& settings, ParticleData& particleData);

  // Perform Bose-Einstein corrections on an event.
  bool shiftEvent( Event& event); 

private: 

  // Constants: could only be changed in the code itself.
  static const int    IDHADRON[9], ITABLE[9], NCOMPSTEP;
  static const double STEPSIZE, Q2MIN, COMPRELERR, COMPFACMAX;

  // Initialization data, read from Settings.
  bool   doPion, doKaon, doEta;
  double lambda, QRef;

  // Pointer to various information on the generation.
  Info* infoPtr;

  // Table of momentum shifts for different hadron species.
  int    nStep[4], nStep3[4], nStored[10];
  double QRef2, QRef3, R2Ref, R2Ref2, R2Ref3, mHadron[9],
         mPair[4], m2Pair[4], deltaQ[4], deltaQ3[4], maxQ[4], maxQ3[4];
  double shift[4][200], shift3[4][200]; 

  // Vector of hadrons to study.
  vector<BoseEinsteinHadron> hadronBE;

  // Calculate shift and (unnormalized) compensation for pair.
  void shiftPair(int i1, int i2, int iHad);
  
};
 
//==========================================================================

} // end namespace Pythia8

#endif // Pythia8_BoseEinstein_H
Commit	Line	Data
9419eeef	1	// Bose-Einstein.h is a part of the PYTHIA event generator.
	2	// Copyright (C) 2010 Torbjorn Sjostrand.
	3	// PYTHIA is licenced under the GNU GPL version 2, see COPYING for details.
	4	// Please respect the MCnet Guidelines, see GUIDELINES for details.
	5
	6	// This file contains the classes to handle Bose-Einstein effects.
	7	// BoseEinsteinHadron: simple working container for particle momenta.
	8	// BoseEinstein: main class to perform the task.
	9
	10	#ifndef Pythia8_BoseEinstein_H
	11	#define Pythia8_BoseEinstein_H
	12
	13	#include "Basics.h"
	14	#include "Event.h"
	15	#include "ParticleData.h"
	16	#include "PythiaStdlib.h"
	17	#include "Settings.h"
	18
	19	namespace Pythia8 {
	20
	21	//==========================================================================
	22
	23	// The BoseEinsteinHadron class is a simple container for studied hadrons.
	24
	25	class BoseEinsteinHadron {
	26
	27	public:
	28
	29	// Constructors.
	30	BoseEinsteinHadron() : id(0), iPos(0), p(0.), pShift(0.), pComp(0.),
	31	m2(0.) {}
	32	BoseEinsteinHadron(int idIn, int iPosIn, Vec4 pIn, double mIn) :
	33	id(idIn), iPos(iPosIn), p(pIn), pShift(0.), pComp(0.) {m2 = mIn*mIn;}
	34
	35	// Information on hadron - all public.
	36	int id, iPos;
	37	Vec4 p, pShift, pComp;
	38	double m2;
	39
	40	};
	41
	42	//==========================================================================
	43
	44	// The BoseEinstein class shifts the momenta of identical particles relative
	45	// to each other, to simulate Bose-Einstein effects to some approximation.
	46
	47	class BoseEinstein {
	48
	49	public:
	50
	51	// Constructor.
	52	BoseEinstein() {}
	53
	54	// Find settings. Precalculate table used to find momentum shifts.
	55	bool init(Info* infoPtrIn, Settings& settings, ParticleData& particleData);
	56
	57	// Perform Bose-Einstein corrections on an event.
	58	bool shiftEvent( Event& event);
	59
	60	private:
	61
	62	// Constants: could only be changed in the code itself.
	63	static const int IDHADRON[9], ITABLE[9], NCOMPSTEP;
	64	static const double STEPSIZE, Q2MIN, COMPRELERR, COMPFACMAX;
65
66	// Initialization data, read from Settings.
67	bool doPion, doKaon, doEta;
68	double lambda, QRef;
69
70	// Pointer to various information on the generation.
71	Info* infoPtr;
72
73	// Table of momentum shifts for different hadron species.
74	int nStep[4], nStep3[4], nStored[10];
75	double QRef2, QRef3, R2Ref, R2Ref2, R2Ref3, mHadron[9],
76	mPair[4], m2Pair[4], deltaQ[4], deltaQ3[4], maxQ[4], maxQ3[4];
77	double shift[4][200], shift3[4][200];
78
79	// Vector of hadrons to study.
80	vector<BoseEinsteinHadron> hadronBE;
81
82	// Calculate shift and (unnormalized) compensation for pair.
83	void shiftPair(int i1, int i2, int iHad);
84
85	};
86
87	//==========================================================================
88
89	} // end namespace Pythia8
90
91	#endif // Pythia8_BoseEinstein_H
92