Line data Source code
1 : // ProcessLevel.h is a part of the PYTHIA event generator.
2 : // Copyright (C) 2015 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 main class for process-level event generation.
7 : // ProcessLevel: administrates the selection of "hard" process.
8 :
9 : #ifndef Pythia8_ProcessLevel_H
10 : #define Pythia8_ProcessLevel_H
11 :
12 : #include "Pythia8/Basics.h"
13 : #include "Pythia8/BeamParticle.h"
14 : #include "Pythia8/Event.h"
15 : #include "Pythia8/Info.h"
16 : #include "Pythia8/ParticleData.h"
17 : #include "Pythia8/PartonDistributions.h"
18 : #include "Pythia8/ProcessContainer.h"
19 : #include "Pythia8/PythiaStdlib.h"
20 : #include "Pythia8/ResonanceDecays.h"
21 : #include "Pythia8/Settings.h"
22 : #include "Pythia8/SigmaTotal.h"
23 : #include "Pythia8/SusyCouplings.h"
24 : #include "Pythia8/SLHAinterface.h"
25 : #include "Pythia8/StandardModel.h"
26 : #include "Pythia8/UserHooks.h"
27 :
28 : namespace Pythia8 {
29 :
30 : //==========================================================================
31 :
32 : // The ProcessLevel class contains the top-level routines to generate
33 : // the characteristic "hard" process of an event.
34 :
35 : class ProcessLevel {
36 :
37 : public:
38 :
39 : // Constructor.
40 0 : ProcessLevel() : iLHACont(-1) {}
41 :
42 : // Destructor to delete processes in containers.
43 : ~ProcessLevel();
44 :
45 : // Initialization.
46 : bool init( Info* infoPtrIn, Settings& settings,
47 : ParticleData* particleDataPtrIn, Rndm* rndmPtrIn,
48 : BeamParticle* beamAPtrIn, BeamParticle* beamBPtrIn,
49 : Couplings* couplingsPtrIn, SigmaTotal* sigmaTotPtrIn, bool doLHAin,
50 : SLHAinterface* slhaInterfacePtrIn, UserHooks* userHooksPtrIn,
51 : vector<SigmaProcess*>& sigmaPtrs, vector<PhaseSpace*>& phaseSpacePtrs,
52 : ostream& os = cout);
53 :
54 : // Store or replace Les Houches pointer.
55 0 : void setLHAPtr( LHAup* lhaUpPtrIn) {lhaUpPtr = lhaUpPtrIn;
56 0 : if (iLHACont >= 0) containerPtrs[iLHACont]->setLHAPtr(lhaUpPtr);}
57 :
58 : // Generate the next "hard" process.
59 : bool next( Event& process);
60 :
61 : // Special case: LHA input of resonance decay only.
62 : bool nextLHAdec( Event& process);
63 :
64 : // Accumulate and update statistics (after possible user veto).
65 : void accumulate();
66 :
67 : // Print statistics on cross sections and number of events.
68 : void statistics(bool reset = false, ostream& os = cout);
69 :
70 : // Reset statistics.
71 : void resetStatistics();
72 :
73 : // Add any junctions to the process event record list.
74 : void findJunctions( Event& junEvent);
75 :
76 : // Initialize and call resonance decays separately.
77 : void initDecays( Info* infoPtrIn, ParticleData* particleDataPtrIn,
78 0 : Rndm* rndmPtrIn, LHAup* lhaUpPtrIn) { infoPtr = infoPtrIn;
79 0 : resonanceDecays.init( infoPtrIn, particleDataPtrIn, rndmPtrIn);
80 0 : containerLHAdec.setLHAPtr(lhaUpPtrIn, particleDataPtrIn); }
81 0 : bool nextDecays( Event& process) { return resonanceDecays.next( process);}
82 :
83 : private:
84 :
85 : // Constants: could only be changed in the code itself.
86 : static const int MAXLOOP;
87 :
88 : // Generic info for process generation.
89 : bool doSecondHard, doSameCuts, allHardSame, noneHardSame,
90 : someHardSame, cutsAgree, cutsOverlap, doResDecays;
91 : int nImpact, startColTag;
92 : double mHatMin1, mHatMax1, pTHatMin1, pTHatMax1, mHatMin2, mHatMax2,
93 : pTHatMin2, pTHatMax2, sigmaND, sumImpactFac, sum2ImpactFac;
94 :
95 : // Vector of containers of internally-generated processes.
96 : vector<ProcessContainer*> containerPtrs;
97 : int iContainer, iLHACont;
98 : double sigmaMaxSum;
99 :
100 : // Ditto for optional choice of a second hard process.
101 : vector<ProcessContainer*> container2Ptrs;
102 : int i2Container;
103 : double sigma2MaxSum;
104 :
105 : // Single half-dummy container for LHA input of resonance decay only.
106 : ProcessContainer containerLHAdec;
107 :
108 : // Pointer to various information on the generation.
109 : Info* infoPtr;
110 :
111 : // Pointer to the particle data table.
112 : ParticleData* particleDataPtr;
113 :
114 : // Pointer to the random number generator.
115 : Rndm* rndmPtr;
116 :
117 : // Pointers to the two incoming beams.
118 : BeamParticle* beamAPtr;
119 : BeamParticle* beamBPtr;
120 :
121 : // Pointer to Standard Model couplings, including alphaS and alphaEM.
122 : Couplings* couplingsPtr;
123 :
124 : // Pointer to SigmaTotal object needed to handle soft QCD processes.
125 : SigmaTotal* sigmaTotPtr;
126 :
127 : // Pointer to SusyLesHouches object for interface to SUSY spectra.
128 : SLHAinterface* slhaInterfacePtr;
129 :
130 : // Pointer to userHooks object for user interaction with program.
131 : UserHooks* userHooksPtr;
132 :
133 : // Pointer to LHAup for generating external events.
134 : LHAup* lhaUpPtr;
135 :
136 : // ResonanceDecay object does sequential resonance decays.
137 : ResonanceDecays resonanceDecays;
138 :
139 : // Generate the next event with one interaction.
140 : bool nextOne( Event& process);
141 :
142 : // Generate the next event with two hard interactions.
143 : bool nextTwo( Event& process);
144 :
145 : // Append the second to the first process list.
146 : void combineProcessRecords( Event& process, Event& process2);
147 :
148 : // Check that colours match up.
149 : bool checkColours( Event& process);
150 :
151 : // Print statistics when two hard processes allowed.
152 : void statistics2(bool reset, ostream& os = cout);
153 :
154 : };
155 :
156 : //==========================================================================
157 :
158 : } // end namespace Pythia8
159 :
160 : #endif // Pythia8_ProcessLevel_H
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