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63ba5337 | 1 | // main06.cc is a part of the PYTHIA event generator. |
2 | // Copyright (C) 2012 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 is a simple test program. | |
7 | // It studies event properties of LEP1 events. | |
8 | ||
9 | #include "Pythia.h" | |
10 | ||
11 | using namespace Pythia8; | |
12 | ||
13 | int main() { | |
14 | ||
15 | // Generator. | |
16 | Pythia pythia; | |
17 | ||
18 | // Allow no substructure in e+- beams: normal for corrected LEP data. | |
19 | pythia.readString("PDF:lepton = off"); | |
20 | // Process selection. | |
21 | pythia.readString("WeakSingleBoson:ffbar2gmZ = on"); | |
22 | // Switch off all Z0 decays and then switch back on those to quarks. | |
23 | pythia.readString("23:onMode = off"); | |
24 | pythia.readString("23:onIfAny = 1 2 3 4 5"); | |
25 | ||
26 | // LEP1 initialization at Z0 mass. | |
27 | pythia.readString("Beams:idA = 11"); | |
28 | pythia.readString("Beams:idB = -11"); | |
29 | double mZ = pythia.particleData.m0(23); | |
30 | pythia.settings.parm("Beams:eCM", mZ); | |
31 | pythia.init(); | |
32 | ||
33 | // Histograms. | |
34 | Hist nCharge("charged multiplicity", 100, -0.5, 99.5); | |
35 | Hist spheri("Sphericity", 100, 0., 1.); | |
36 | Hist linea("Linearity", 100, 0., 1.); | |
37 | Hist thrust("thrust", 100, 0.5, 1.); | |
38 | Hist oblateness("oblateness", 100, 0., 1.); | |
39 | Hist sAxis("cos(theta_Sphericity)", 100, -1., 1.); | |
40 | Hist lAxis("cos(theta_Linearity)", 100, -1., 1.); | |
41 | Hist tAxis("cos(theta_Thrust)", 100, -1., 1.); | |
42 | Hist nLund("Lund jet multiplicity", 40, -0.5, 39.5); | |
43 | Hist nJade("Jade jet multiplicity", 40, -0.5, 39.5); | |
44 | Hist nDurham("Durham jet multiplicity", 40, -0.5, 39.5); | |
45 | Hist eDifLund("Lund e_i - e_{i+1}", 100, -5.,45.); | |
46 | Hist eDifJade("Jade e_i - e_{i+1}", 100, -5.,45.); | |
47 | Hist eDifDurham("Durham e_i - e_{i+1}", 100, -5.,45.); | |
48 | ||
49 | // Set up Sphericity, "Linearity", Thrust and cluster jet analyses. | |
50 | Sphericity sph; | |
51 | Sphericity lin(1.); | |
52 | Thrust thr; | |
53 | ClusterJet lund("Lund"); | |
54 | ClusterJet jade("Jade"); | |
55 | ClusterJet durham("Durham"); | |
56 | ||
57 | // Begin event loop. Generate event. Skip if error. List first few. | |
58 | for (int iEvent = 0; iEvent < 10000; ++iEvent) { | |
59 | if (!pythia.next()) continue; | |
60 | ||
61 | // Find and histogram charged multiplicity. | |
62 | int nCh = 0; | |
63 | for (int i = 0; i < pythia.event.size(); ++i) | |
64 | if (pythia.event[i].isFinal() && pythia.event[i].isCharged()) ++nCh; | |
65 | nCharge.fill( nCh ); | |
66 | ||
67 | // Find and histogram sphericity. | |
68 | if (sph.analyze( pythia.event )) { | |
69 | if (iEvent < 3) sph.list(); | |
70 | spheri.fill( sph.sphericity() ); | |
71 | sAxis.fill( sph.eventAxis(1).pz() ); | |
72 | double e1 = sph.eigenValue(1); | |
73 | double e2 = sph.eigenValue(2); | |
74 | double e3 = sph.eigenValue(3); | |
75 | if (e2 > e1 || e3 > e2) cout << "eigenvalues out of order: " | |
76 | << e1 << " " << e2 << " " << e3 << endl; | |
77 | } | |
78 | ||
79 | // Find and histogram linearized sphericity. | |
80 | if (lin.analyze( pythia.event )) { | |
81 | if (iEvent < 3) lin.list(); | |
82 | linea.fill( lin.sphericity() ); | |
83 | lAxis.fill( lin.eventAxis(1).pz() ); | |
84 | double e1 = lin.eigenValue(1); | |
85 | double e2 = lin.eigenValue(2); | |
86 | double e3 = lin.eigenValue(3); | |
87 | if (e2 > e1 || e3 > e2) cout << "eigenvalues out of order: " | |
88 | << e1 << " " << e2 << " " << e3 << endl; | |
89 | } | |
90 | ||
91 | // Find and histogram thrust. | |
92 | if (thr.analyze( pythia.event )) { | |
93 | if (iEvent < 3) thr.list(); | |
94 | thrust.fill( thr.thrust() ); | |
95 | oblateness.fill( thr.oblateness() ); | |
96 | tAxis.fill( thr.eventAxis(1).pz() ); | |
97 | if ( abs(thr.eventAxis(1).pAbs() - 1.) > 1e-8 | |
98 | || abs(thr.eventAxis(2).pAbs() - 1.) > 1e-8 | |
99 | || abs(thr.eventAxis(3).pAbs() - 1.) > 1e-8 | |
100 | || abs(thr.eventAxis(1) * thr.eventAxis(2)) > 1e-8 | |
101 | || abs(thr.eventAxis(1) * thr.eventAxis(3)) > 1e-8 | |
102 | || abs(thr.eventAxis(2) * thr.eventAxis(3)) > 1e-8 ) { | |
103 | cout << " suspicious Thrust eigenvectors " << endl; | |
104 | thr.list(); | |
105 | } | |
106 | } | |
107 | ||
108 | // Find and histogram cluster jets: Lund, Jade and Durham distance. | |
109 | if (lund.analyze( pythia.event, 0.01, 0.)) { | |
110 | if (iEvent < 3) lund.list(); | |
111 | nLund.fill( lund.size() ); | |
112 | for (int j = 0; j < lund.size() - 1; ++j) | |
113 | eDifLund.fill( lund.p(j).e() - lund.p(j+1).e() ); | |
114 | } | |
115 | if (jade.analyze( pythia.event, 0.01, 0.)) { | |
116 | if (iEvent < 3) jade.list(); | |
117 | nJade.fill( jade.size() ); | |
118 | for (int j = 0; j < jade.size() - 1; ++j) | |
119 | eDifJade.fill( jade.p(j).e() - jade.p(j+1).e() ); | |
120 | } | |
121 | if (durham.analyze( pythia.event, 0.01, 0.)) { | |
122 | if (iEvent < 3) durham.list(); | |
123 | nDurham.fill( durham.size() ); | |
124 | for (int j = 0; j < durham.size() - 1; ++j) | |
125 | eDifDurham.fill( durham.p(j).e() - durham.p(j+1).e() ); | |
126 | } | |
127 | ||
128 | // End of event loop. Statistics. Output histograms. | |
129 | } | |
130 | pythia.stat(); | |
131 | cout << nCharge << spheri << linea << thrust << oblateness | |
132 | << sAxis << lAxis << tAxis | |
133 | << nLund << nJade << nDurham | |
134 | << eDifLund << eDifJade << eDifDurham; | |
135 | ||
136 | // Done. | |
137 | return 0; | |
138 | } |