Line data Source code
1 : // PartonLevel.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 parton-level event generation
7 : // PartonLevel: administrates showers, multiparton interactions and remnants.
8 :
9 : #ifndef Pythia8_PartonLevel_H
10 : #define Pythia8_PartonLevel_H
11 :
12 : #include "Pythia8/Basics.h"
13 : #include "Pythia8/BeamParticle.h"
14 : #include "Pythia8/BeamRemnants.h"
15 : #include "Pythia8/ColourReconnection.h"
16 : #include "Pythia8/Event.h"
17 : #include "Pythia8/HardDiffraction.h"
18 : #include "Pythia8/Info.h"
19 : #include "Pythia8/JunctionSplitting.h"
20 : #include "Pythia8/MergingHooks.h"
21 : #include "Pythia8/MultipartonInteractions.h"
22 : #include "Pythia8/ParticleData.h"
23 : #include "Pythia8/PartonSystems.h"
24 : #include "Pythia8/PythiaStdlib.h"
25 : #include "Pythia8/ResonanceDecays.h"
26 : #include "Pythia8/RHadrons.h"
27 : #include "Pythia8/Settings.h"
28 : #include "Pythia8/SigmaTotal.h"
29 : #include "Pythia8/SpaceShower.h"
30 : #include "Pythia8/StandardModel.h"
31 : #include "Pythia8/StringLength.h"
32 : #include "Pythia8/TimeShower.h"
33 : #include "Pythia8/UserHooks.h"
34 :
35 :
36 : namespace Pythia8 {
37 :
38 : //==========================================================================
39 :
40 : // The PartonLevel class contains the top-level routines to generate
41 : // the partonic activity of an event.
42 :
43 0 : class PartonLevel {
44 :
45 : public:
46 :
47 : // Constructor.
48 0 : PartonLevel() : userHooksPtr(0) {}
49 :
50 : // Initialization of all classes at the parton level.
51 : bool init( Info* infoPtrIn, Settings& settings,
52 : ParticleData* particleDataPtrIn, Rndm* rndmPtrIn,
53 : BeamParticle* beamAPtrIn, BeamParticle* beamBPtrIn,
54 : BeamParticle* beamPomAPtrIn, BeamParticle* beamPomBPtrIn,
55 : Couplings* couplingsPtrIn, PartonSystems* partonSystemsPtrIn,
56 : SigmaTotal* sigmaTotPtr, TimeShower* timesDecPtrIn,
57 : TimeShower* timesPtrIn, SpaceShower* spacePtrIn,
58 : RHadrons* rHadronsPtrIn, UserHooks* userHooksPtrIn,
59 : MergingHooks* mergingHooksPtr, bool useAsTrial);
60 :
61 : // Generate the next parton-level process.
62 : bool next( Event& process, Event& event);
63 :
64 : // Perform showers in resonance decay chains. (For special cases.)
65 : void setupShowerSys( Event& process, Event& event);
66 : bool resonanceShowers( Event& process, Event& event, bool skipForR);
67 :
68 : // Perform decays and showers of W and Z emitted in shower.
69 : bool wzDecayShowers( Event& event);
70 :
71 : // Tell whether failure was due to vetoing.
72 0 : bool hasVetoed() const {return doVeto;}
73 0 : bool hasVetoedDiff() const {return doDiffVeto;}
74 :
75 : // Accumulate, print and reset statistics.
76 0 : void accumulate() {if (isResolved && !isDiff) multiPtr->accumulate();}
77 : void statistics(bool reset = false) {
78 0 : if (doMPI) multiMB.statistics(reset);}
79 : // For now no separate statistics for diffraction??
80 : //if (doMPISDA && doDiffraction) multiSDA.statistics(reset);
81 : //if (doMPISDB && doDiffraction) multiSDB.statistics(reset);}
82 0 : void resetStatistics() { if (doMPI) multiMB.resetStatistics(); }
83 :
84 : // Reset PartonLevel object for trial shower usage.
85 : void resetTrial();
86 : // Provide the pT scale of the last branching in the shower.
87 0 : double pTLastInShower(){ return pTLastBranch; }
88 : // Provide the type of the last branching in the shower.
89 0 : int typeLastInShower(){ return typeLastBranch; }
90 :
91 : private:
92 :
93 : // Constants: could only be changed in the code itself.
94 : static const int NTRY;
95 :
96 : // Initialization data, mainly read from Settings.
97 : bool doNonDiff, doDiffraction, doMPI, doMPIMB, doMPISDA, doMPISDB,
98 : doMPICD, doMPIinit, doISR, doFSRduringProcess, doFSRafterProcess,
99 : doFSRinResonances, doRemnants, doSecondHard, hasOneLeptonBeam,
100 : hasTwoLeptonBeams, hasPointLeptons, canVetoPT, canVetoStep,
101 : canVetoMPIStep, canVetoEarly, canSetScale, allowRH, earlyResDec,
102 : vetoWeakJets, canReconResSys, doReconnect, doHardDiff,
103 : forceResonanceCR;
104 : double mMinDiff, mWidthDiff, pMaxDiff, vetoWeakDeltaR2;
105 :
106 : // Event generation strategy. Number of steps. Maximum pT scales.
107 : bool doVeto;
108 : int nMPI, nISR, nFSRinProc, nFSRinRes, nISRhard, nFSRhard,
109 : typeLatest, nVetoStep, typeVetoStep, nVetoMPIStep, iSysNow,
110 : reconnectMode, sampleTypeDiff;
111 : double pTsaveMPI, pTsaveISR, pTsaveFSR, pTvetoPT;
112 :
113 : // Current event properties.
114 : bool isNonDiff, isDiffA, isDiffB, isDiffC, isDiff, isSingleDiff,
115 : isDoubleDiff, isCentralDiff, isResolved, isResolvedA,
116 : isResolvedB, isResolvedC, isHardDiffA, isHardDiffB, isHardDiff,
117 : isSetupDiff, doDiffVeto;
118 : int sizeProcess, sizeEvent, nHardDone, nHardDoneRHad, iDS;
119 : double eCMsave;
120 : vector<bool> inRHadDecay;
121 : vector<int> iPosBefShow;
122 :
123 : // Pointer to various information on the generation.
124 : Info* infoPtr;
125 :
126 : // Pointer to the particle data table.
127 : ParticleData* particleDataPtr;
128 :
129 : // Pointer to the random number generator.
130 : Rndm* rndmPtr;
131 :
132 : // Pointers to the two incoming beams.
133 : BeamParticle* beamAPtr;
134 : BeamParticle* beamBPtr;
135 :
136 : // Spare copies of normal pointers. Pointers to Pomeron beam-inside-beam.
137 : BeamParticle* beamHadAPtr;
138 : BeamParticle* beamHadBPtr;
139 : BeamParticle* beamPomAPtr;
140 : BeamParticle* beamPomBPtr;
141 :
142 : // Pointers to Standard Model couplings.
143 : Couplings* couplingsPtr;
144 :
145 : // Pointer to information on subcollision parton locations.
146 : PartonSystems* partonSystemsPtr;
147 :
148 : // Pointer to userHooks object for user interaction with program.
149 : UserHooks* userHooksPtr;
150 :
151 : // Pointers to timelike showers for resonance decays and the rest.
152 : TimeShower* timesDecPtr;
153 : TimeShower* timesPtr;
154 :
155 : // Pointer to spacelike showers.
156 : SpaceShower* spacePtr;
157 :
158 : // The generator classes for multiparton interactions.
159 : MultipartonInteractions multiMB;
160 : MultipartonInteractions multiSDA;
161 : MultipartonInteractions multiSDB;
162 : MultipartonInteractions multiCD;
163 : MultipartonInteractions* multiPtr;
164 :
165 : // The generator class to construct beam-remnant kinematics.
166 : BeamRemnants remnants;
167 :
168 : // The RHadrons class is used to fragment off and decay R-hadrons.
169 : RHadrons* rHadronsPtr;
170 :
171 : // ResonanceDecay object does sequential resonance decays.
172 : ResonanceDecays resonanceDecays;
173 :
174 : // The Colour reconnection class used to do colour reconnection.
175 : ColourReconnection colourReconnection;
176 :
177 : // The Junction splitting class used to split junctions systems.
178 : JunctionSplitting junctionSplitting;
179 :
180 : // The Diffraction class is for hard diffraction selection.
181 : HardDiffraction hardDiffraction;
182 :
183 : // Resolved diffraction: find how many systems should have it.
184 : int decideResolvedDiff( Event& process);
185 :
186 : // Set up an unresolved process, i.e. elastic or diffractive.
187 : bool setupUnresolvedSys( Event& process, Event& event);
188 :
189 : // Set up the hard process, excluding subsequent resonance decays.
190 : void setupHardSys( Event& process, Event& event);
191 :
192 : // Resolved diffraction: pick whether to have it and set up for it.
193 : void setupResolvedDiff( Event& process);
194 :
195 : // Resolved diffraction: restore normal behaviour.
196 : void leaveResolvedDiff( int iHardLoop, Event& process, Event& event);
197 :
198 : // Hard diffraction: set up the process record.
199 : void setupHardDiff( Event& process);
200 :
201 : // Hard diffraction: leave the process record.
202 : void leaveHardDiff( Event& process, Event& event);
203 :
204 : // Pointer to MergingHooks object for user interaction with the merging.
205 : MergingHooks* mergingHooksPtr;
206 : // Parameters to specify trial shower usage.
207 : bool doTrial;
208 : int nTrialEmissions;
209 : // Parameters to store to veto trial showers.
210 : double pTLastBranch;
211 : int typeLastBranch;
212 : // Parameters to specify merging usage.
213 : bool canRemoveEvent, canRemoveEmission;
214 :
215 : };
216 :
217 : //==========================================================================
218 :
219 : } // end namespace Pythia8
220 :
221 : #endif // Pythia8_PartonLevel_H
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