| 1 | //--------------------------------------------------------------------------
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| 2 | #ifndef HEPMC_PARTICLE_DATA_H
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| 3 | #define HEPMC_PARTICLE_DATA_H
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| 4 |
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| 5 | //////////////////////////////////////////////////////////////////////////
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| 6 | // Matt.Dobbs@Cern.CH, September 1999, refer to:
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| 7 | // M. Dobbs and J.B. Hansen, "The HepMC C++ Monte Carlo Event Record for
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| 8 | // High Energy Physics", Computer Physics Communications (to be published).
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| 9 | //
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| 10 | // GenParticle Data common to all particles of a given PDG id
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| 11 | //////////////////////////////////////////////////////////////////////////
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| 12 | //
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| 13 | // Units ID: defined by PDG group (particles are +ve, antiparticles are -ve)
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| 14 | // also consistent with the Pythia definitions
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| 15 | // See: http://d0lblt.lbl.gov/wwwpdg/mc_numbers.htm
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| 16 | // charge: fraction of proton charge
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| 17 | // mass in user defined energy units
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| 18 | // width: ( stored as cLifetime = hbar / Width )
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| 19 | // cLifetime: c*time
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| 20 | // spin: fraction of photon spin (always a positive number)
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| 21 | //
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| 22 | // Default mass is 0.
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| 23 | // Default cLifetime is -1 which means stable (setting width = 0 gives this)
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| 24 | // (we define cLifetime = -1 --> width = 0 (i.e stable),
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| 25 | // width = -1 --> cLifetime = 0 (i.e. prompt) )
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| 26 | // These defaults exist because many very basic MC generators
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| 27 | // may produce only massless stable particles in the event record.
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| 28 | //
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| 29 | // It is intended that a different ParticleData object is created for each
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| 30 | // particle and its anti-particle - useful for CP violation studies.
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| 31 | //
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| 32 | // There are few set methods for this class, there should be no reason
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| 33 | // to change anything after instantiating. If you need to, then
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| 34 | // create a new object and kill the old one.
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| 35 | //
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| 36 | // Example:
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| 37 | // HepMC::ParticleData* pd_electron =
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| 38 | // new HepMC::ParticleData("electron",11,-1,0.000511,-1,.5);
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| 39 | // A method is provided to allow you to set the lifetime from the
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| 40 | // width in the constructor
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| 41 | // Example: new HepMC::ParticleData("W+",24,+1,80.396,
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| 42 | // HepMC::clifetime_from_width(2.06),1);
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| 43 | // Example of finding a ParticleData object from its PDG ID
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| 44 | // in ParticleDataTable pdt:
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| 45 | // HepMC::ParticleData* electron = pdt.find(11);
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| 46 | // or if you just wanted two know the electron mass, you could do:
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| 47 | // pdt.find(11)->mass();
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| 48 |
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| 49 | #include <iostream>
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| 50 | #include <string>
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| 51 | #include <stdlib.h> // for integer abs()
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| 52 |
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| 53 | namespace HepMC {
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| 54 |
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| 55 | /// hbar * c --> calculated with units of [mm*GeV]
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| 56 | static const double HepMC_hbarc = (6.6260755e-34 * (1.e-6/1.60217733e-19) / (2*3.14159265358979323846))
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| 57 | * (2.99792458e+8 * 1000.) * 1.e+3;
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| 58 |
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| 59 | // if you want to instantiate the particle lifetime from its width,
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| 60 | // use this static method inside the constructor:
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| 61 | double clifetime_from_width( double width ); //!< set lifetime from width
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| 62 |
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| 63 | //! an example ParticleData class
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| 64 |
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| 65 | ///
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| 66 | /// \class ParticleData
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| 67 | /// Particle Data common to all particles of a given PDG id
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| 68 | ///
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| 69 | class ParticleData {
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| 70 |
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| 71 | friend std::ostream& operator<<( std::ostream&, const ParticleData& );
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| 72 |
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| 73 | public:
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| 74 | /// constructor requiring name, ID, and charge
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| 75 | ParticleData( std::string name, int id, double charge, double mass = 0,
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| 76 | double cLifetime = -1, double spin = 0 );
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| 77 | /// constructor requiring name, ID, and charge
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| 78 | ParticleData( const char* name, int id, double charge, double mass = 0,
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| 79 | double cLifetime = -1, double spin = 0 );
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| 80 | virtual ~ParticleData();
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| 81 |
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| 82 | bool operator==( const ParticleData& ) const; //!< equality
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| 83 | bool operator!=( const ParticleData& ) const; //!< inequality
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| 84 |
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| 85 | /// write particle data information to ostr
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| 86 | void print( std::ostream& ostr = std::cout ) const;
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| 87 |
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| 88 | bool is_lepton() const; //!< true if charged lepton /neutrino
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| 89 | bool is_charged_lepton() const;//!< true if a charged lepton
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| 90 | bool is_em() const; //!< true if an electron or photon
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| 91 | bool is_neutrino() const; //!< true if a neutrino
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| 92 | bool is_hadron() const; //!< true if a hadron
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| 93 | bool is_boson() const; //!< true if a gauge or higgs boson
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| 94 |
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| 95 | ////////////////////
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| 96 | // access methods //
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| 97 | ////////////////////
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| 98 |
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| 99 | /// description of the particle according to PDG, i.e. "Delta(1900) S_31"
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| 100 | std::string name() const;
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| 101 | /// PDG ID number
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| 102 | int pdg_id() const;
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| 103 | /// charge
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| 104 | double charge() const;
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| 105 | /// nominal mass
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| 106 | double mass() const;
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| 107 | /// width as calculated from clifetime
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| 108 | double width() const;
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| 109 | /// lifetime in mm
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| 110 | double clifetime() const;
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| 111 | /// J spin
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| 112 | double spin() const;
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| 113 |
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| 114 | void set_charge( double ); //!< set charge
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| 115 | void set_mass( double ); //!< set nominal mass
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| 116 | void set_width( double ); //!< set width
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| 117 | void set_clifetime( double ); //!< set lifetime in mm
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| 118 | void set_spin( double ); //!< set J spin
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| 119 |
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| 120 | protected:
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| 121 | static unsigned int counter(); //!< num ParticleData objects in memory
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| 122 |
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| 123 | /// omits susy/excited/technicolor digit from returned ID
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| 124 | int model_independent_pdg_id_() const;
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| 125 |
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| 126 | private:
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| 127 | std::string m_name; // description of the particle according to PDG
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| 128 | // i.e. "Delta(1900) S_31"
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| 129 | int m_pdg_id; // PDG ID number (note we allow -ve)
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| 130 | int m_3charge;// 3*electric charge in units of proton charge
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| 131 | double m_mass; // nominal mass in user defined energy units
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| 132 | double m_clifetime; // [mm]
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| 133 | unsigned char m_2spin; // 2*spin (J) of particle
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| 134 |
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| 135 | static unsigned int s_counter;
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| 136 | };
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| 137 |
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| 138 | ///////////////////////////
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| 139 | // INLINES //
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| 140 | ///////////////////////////
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| 141 |
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| 142 | inline bool ParticleData::is_lepton() const {
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| 143 | /// true if a charged lepton or neutrino --> | 11,13,15,12,14,16,17,18 |
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| 144 | return ( abs(pdg_id()) >=11 && abs(pdg_id()) <= 18 );
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| 145 | }
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| 146 | inline bool ParticleData::is_charged_lepton() const {
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| 147 | /// true if a charged lepton --> | 11,13,15 |
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| 148 | return ( is_lepton() && abs(pdg_id())%2==1 );
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| 149 | }
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| 150 | inline bool ParticleData::is_neutrino() const {
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| 151 | /// true if a neutrino --> | 12,14,16 |
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| 152 | return ( is_lepton() && abs(pdg_id())%2==0 );
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| 153 | }
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| 154 | inline bool ParticleData::is_em() const {
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| 155 | /// true if an electron or photon --> | 11, 22 |
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| 156 | return ( abs(pdg_id()) == 11 || abs(pdg_id()) == 22 );
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| 157 | }
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| 158 | inline bool ParticleData::is_hadron() const {
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| 159 | /// true if a hadron --> q,g,meson,baryon
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| 160 | return ( abs(pdg_id()) <= 9 || abs(pdg_id()) == 21
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| 161 | || abs(pdg_id()) >100 );
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| 162 | }
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| 163 | inline bool ParticleData::is_boson() const {
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| 164 | /// true if a gauge or higgs boson --> | 9, 21-39 |
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| 165 | return ( ( abs(pdg_id()) >20 && abs(pdg_id()) <=40 )
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| 166 | || abs(pdg_id()) == 9 );
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| 167 | }
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| 168 |
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| 169 | ///////////////////////////
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| 170 | // INLINE Access Methods //
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| 171 | ///////////////////////////
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| 172 |
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| 173 | inline std::string ParticleData::name() const { return m_name; }
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| 174 | inline int ParticleData::pdg_id() const { return m_pdg_id; }
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| 175 | inline double ParticleData::charge() const {
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| 176 | return ( (double)m_3charge )/3.;
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| 177 | }
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| 178 | inline double ParticleData::mass() const { return m_mass; }
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| 179 | inline double ParticleData::clifetime() const { return m_clifetime; }
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| 180 | inline double ParticleData::spin() const { return m_2spin/2.; }
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| 181 | inline void ParticleData::set_charge( double charge ) {
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| 182 | if ( charge > 0 ) {
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| 183 | m_3charge = (int)(3.*charge+.1);
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| 184 | } else if ( charge < 0. ) {
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| 185 | m_3charge = (int)(3.*charge-.1);
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| 186 | } else {
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| 187 | m_3charge = 0;
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| 188 | }
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| 189 | }
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| 190 | inline void ParticleData::set_mass( double its_mass ) {
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| 191 | m_mass = its_mass;
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| 192 | }
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| 193 | inline void ParticleData::set_width( double width ) {
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| 194 | if ( width > 0 ) {
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| 195 | m_clifetime = HepMC_hbarc/width;
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| 196 | } else if ( width == 0. ) {
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| 197 | m_clifetime = -1.;
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| 198 | } else {
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| 199 | m_clifetime = 0.;
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| 200 | }
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| 201 | }
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| 202 | inline void ParticleData::set_clifetime( double its_clifetime ) {
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| 203 | m_clifetime = its_clifetime;
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| 204 | }
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| 205 | inline void ParticleData::set_spin( double spin ) {
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| 206 | m_2spin = (unsigned char)(2.*spin+.1);
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| 207 | }
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| 208 |
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| 209 | ///////////////////////////
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| 210 | // INLINE Operators //
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| 211 | ///////////////////////////
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| 212 |
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| 213 | inline bool ParticleData::operator==( const ParticleData& a ) const {
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| 214 | // compares everything except the particle's name
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| 215 | return ( a.m_pdg_id != m_pdg_id ||
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| 216 | a.m_mass != m_mass ||
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| 217 | a.m_clifetime != m_clifetime ||
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| 218 | a.m_3charge != m_3charge ||
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| 219 | a.m_2spin != m_2spin ) ? 0 : 1;
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| 220 | }
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| 221 |
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| 222 | inline bool ParticleData::operator!=( const ParticleData& a ) const {
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| 223 | // compares everything except the particle's name
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| 224 | return ( a.pdg_id() != this->pdg_id() );
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| 225 | }
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| 226 |
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| 227 | } // HepMC
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| 228 |
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| 229 | #endif // HEPMC_PARTICLE_DATA_H
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| 230 | //--------------------------------------------------------------------------
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| 231 |
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| 232 |
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| 233 |
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