1 | // main06.cc is a part of the PYTHIA event generator. |
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2 | // Copyright (C) 2012 Torbjorn Sjostrand. |
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3 | // PYTHIA is licenced under the GNU GPL version 2, see COPYING for details. |
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4 | // Please respect the MCnet Guidelines, see GUIDELINES for details. |
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5 | |
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6 | // This is a simple test program. |
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7 | // It studies event properties of LEP1 events. |
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8 | |
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9 | #include "Pythia.h" |
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10 | |
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11 | using namespace Pythia8; |
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12 | |
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13 | int main() { |
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14 | |
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15 | // Generator. |
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16 | Pythia pythia; |
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17 | |
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18 | // Allow no substructure in e+- beams: normal for corrected LEP data. |
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19 | pythia.readString("PDF:lepton = off"); |
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20 | // Process selection. |
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21 | pythia.readString("WeakSingleBoson:ffbar2gmZ = on"); |
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22 | // Switch off all Z0 decays and then switch back on those to quarks. |
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23 | pythia.readString("23:onMode = off"); |
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24 | pythia.readString("23:onIfAny = 1 2 3 4 5"); |
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25 | |
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26 | // LEP1 initialization at Z0 mass. |
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27 | pythia.readString("Beams:idA = 11"); |
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28 | pythia.readString("Beams:idB = -11"); |
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29 | double mZ = pythia.particleData.m0(23); |
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30 | pythia.settings.parm("Beams:eCM", mZ); |
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31 | pythia.init(); |
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32 | |
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33 | // Histograms. |
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34 | Hist nCharge("charged multiplicity", 100, -0.5, 99.5); |
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35 | Hist spheri("Sphericity", 100, 0., 1.); |
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36 | Hist linea("Linearity", 100, 0., 1.); |
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37 | Hist thrust("thrust", 100, 0.5, 1.); |
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38 | Hist oblateness("oblateness", 100, 0., 1.); |
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39 | Hist sAxis("cos(theta_Sphericity)", 100, -1., 1.); |
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40 | Hist lAxis("cos(theta_Linearity)", 100, -1., 1.); |
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41 | Hist tAxis("cos(theta_Thrust)", 100, -1., 1.); |
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42 | Hist nLund("Lund jet multiplicity", 40, -0.5, 39.5); |
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43 | Hist nJade("Jade jet multiplicity", 40, -0.5, 39.5); |
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44 | Hist nDurham("Durham jet multiplicity", 40, -0.5, 39.5); |
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45 | Hist eDifLund("Lund e_i - e_{i+1}", 100, -5.,45.); |
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46 | Hist eDifJade("Jade e_i - e_{i+1}", 100, -5.,45.); |
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47 | Hist eDifDurham("Durham e_i - e_{i+1}", 100, -5.,45.); |
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48 | |
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49 | // Set up Sphericity, "Linearity", Thrust and cluster jet analyses. |
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50 | Sphericity sph; |
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51 | Sphericity lin(1.); |
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52 | Thrust thr; |
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53 | ClusterJet lund("Lund"); |
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54 | ClusterJet jade("Jade"); |
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55 | ClusterJet durham("Durham"); |
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56 | |
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57 | // Begin event loop. Generate event. Skip if error. List first few. |
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58 | for (int iEvent = 0; iEvent < 10000; ++iEvent) { |
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59 | if (!pythia.next()) continue; |
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60 | |
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61 | // Find and histogram charged multiplicity. |
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62 | int nCh = 0; |
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63 | for (int i = 0; i < pythia.event.size(); ++i) |
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64 | if (pythia.event[i].isFinal() && pythia.event[i].isCharged()) ++nCh; |
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65 | nCharge.fill( nCh ); |
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66 | |
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67 | // Find and histogram sphericity. |
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68 | if (sph.analyze( pythia.event )) { |
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69 | if (iEvent < 3) sph.list(); |
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70 | spheri.fill( sph.sphericity() ); |
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71 | sAxis.fill( sph.eventAxis(1).pz() ); |
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72 | double e1 = sph.eigenValue(1); |
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73 | double e2 = sph.eigenValue(2); |
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74 | double e3 = sph.eigenValue(3); |
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75 | if (e2 > e1 || e3 > e2) cout << "eigenvalues out of order: " |
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76 | << e1 << " " << e2 << " " << e3 << endl; |
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77 | } |
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78 | |
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79 | // Find and histogram linearized sphericity. |
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80 | if (lin.analyze( pythia.event )) { |
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81 | if (iEvent < 3) lin.list(); |
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82 | linea.fill( lin.sphericity() ); |
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83 | lAxis.fill( lin.eventAxis(1).pz() ); |
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84 | double e1 = lin.eigenValue(1); |
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85 | double e2 = lin.eigenValue(2); |
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86 | double e3 = lin.eigenValue(3); |
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87 | if (e2 > e1 || e3 > e2) cout << "eigenvalues out of order: " |
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88 | << e1 << " " << e2 << " " << e3 << endl; |
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89 | } |
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90 | |
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91 | // Find and histogram thrust. |
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92 | if (thr.analyze( pythia.event )) { |
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93 | if (iEvent < 3) thr.list(); |
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94 | thrust.fill( thr.thrust() ); |
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95 | oblateness.fill( thr.oblateness() ); |
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96 | tAxis.fill( thr.eventAxis(1).pz() ); |
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97 | if ( abs(thr.eventAxis(1).pAbs() - 1.) > 1e-8 |
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98 | || abs(thr.eventAxis(2).pAbs() - 1.) > 1e-8 |
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99 | || abs(thr.eventAxis(3).pAbs() - 1.) > 1e-8 |
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100 | || abs(thr.eventAxis(1) * thr.eventAxis(2)) > 1e-8 |
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101 | || abs(thr.eventAxis(1) * thr.eventAxis(3)) > 1e-8 |
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102 | || abs(thr.eventAxis(2) * thr.eventAxis(3)) > 1e-8 ) { |
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103 | cout << " suspicious Thrust eigenvectors " << endl; |
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104 | thr.list(); |
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105 | } |
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106 | } |
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107 | |
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108 | // Find and histogram cluster jets: Lund, Jade and Durham distance. |
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109 | if (lund.analyze( pythia.event, 0.01, 0.)) { |
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110 | if (iEvent < 3) lund.list(); |
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111 | nLund.fill( lund.size() ); |
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112 | for (int j = 0; j < lund.size() - 1; ++j) |
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113 | eDifLund.fill( lund.p(j).e() - lund.p(j+1).e() ); |
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114 | } |
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115 | if (jade.analyze( pythia.event, 0.01, 0.)) { |
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116 | if (iEvent < 3) jade.list(); |
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117 | nJade.fill( jade.size() ); |
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118 | for (int j = 0; j < jade.size() - 1; ++j) |
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119 | eDifJade.fill( jade.p(j).e() - jade.p(j+1).e() ); |
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120 | } |
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121 | if (durham.analyze( pythia.event, 0.01, 0.)) { |
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122 | if (iEvent < 3) durham.list(); |
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123 | nDurham.fill( durham.size() ); |
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124 | for (int j = 0; j < durham.size() - 1; ++j) |
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125 | eDifDurham.fill( durham.p(j).e() - durham.p(j+1).e() ); |
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126 | } |
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127 | |
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128 | // End of event loop. Statistics. Output histograms. |
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129 | } |
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130 | pythia.stat(); |
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131 | cout << nCharge << spheri << linea << thrust << oblateness |
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132 | << sAxis << lAxis << tAxis |
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133 | << nLund << nJade << nDurham |
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134 | << eDifLund << eDifJade << eDifDurham; |
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135 | |
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136 | // Done. |
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137 | return 0; |
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138 | } |
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