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PYTHIA
8.312
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A derived class for q qbar -> g g g. More...
#include <SigmaQCD.h>
Public Member Functions | |
| Sigma3qqbar2ggg () | |
| Constructor. | |
| virtual void | sigmaKin () |
| Calculate flavour-independent parts of cross section. More... | |
| virtual double | sigmaHat () |
| Evaluate d(sigmaHat)/d(tHat). | |
| virtual void | setIdColAcol () |
| Select flavour, colour and anticolour. More... | |
| virtual string | name () const |
| Info on the subprocess. | |
| virtual int | code () const |
| virtual int | nFinal () const |
| Number of final-state particles. | |
| virtual string | inFlux () const |
| Need to know which incoming partons to set up interaction for. | |
| virtual bool | isQCD3body () const |
| QCD 2 -> 3 processes need special phase space selection machinery. | |
 Public Member Functions inherited from Sigma3Process | |
| virtual | ~Sigma3Process () |
| Destructor. | |
| virtual void | set3Kin (double x1in, double x2in, double sHin, Vec4 p3cmIn, Vec4 p4cmIn, Vec4 p5cmIn, double m3in, double m4in, double m5in, double runBW3in, double runBW4in, double runBW5in) |
| Input and complement kinematics for resolved 2 -> 3 process. | |
| Public Member Functions inherited from SigmaProcess | |
| virtual | ~SigmaProcess () |
| Destructor. | |
| void | init (BeamParticle *beamAPtrIn, BeamParticle *beamBPtrIn, SLHAinterface *slhaInterfacePtrIn=0) |
| Perform simple initialization and store pointers. More... | |
| void | setLHAPtr (LHAupPtr lhaUpPtrIn) |
| Store or replace Les Houches pointer. | |
| void | updateBeamIDs () |
| Switch to new beam particle identities; for similar hadrons only. | |
| virtual void | initProc () |
| Initialize process. Only used for some processes. | |
| virtual bool | initFlux () |
| Set up allowed flux of incoming partons. Default is no flux. More... | |
| virtual void | set1Kin (double, double, double) |
| virtual void | set2Kin (double, double, double, double, double, double, double, double) |
| virtual void | set2KinMPI (double, double, double, double, double, double, double, bool, double, double) |
| virtual double | sigmaHatWrap (int id1in=0, int id2in=0) |
| virtual double | sigmaPDF (bool initPS=false, bool samexGamma=false, bool useNewXvalues=false, double x1New=0., double x2New=0.) |
| void | pickInState (int id1in=0, int id2in=0) |
| Select incoming parton channel and extract parton densities (resolved). More... | |
| virtual bool | final2KinMPI (int=0, int=0, Vec4=0., Vec4=0., double=0., double=0.) |
| Perform kinematics for a Multiparton Interaction, in its rest frame. | |
| virtual double | weightDecay (Event &, int, int) |
| virtual void | setScale () |
| Set scale, when that is missing for an external LHA process. | |
| virtual bool | convert2mb () const |
| Need to know whether to convert cross section answer from GeV^-2 to mb. | |
| virtual bool | convertM2 () const |
| For 2 -> 2 process optional conversion from |M|^2 to d(sigmaHat)/d(tHat). | |
| virtual bool | isLHA () const |
| Special treatment needed for Les Houches processes. | |
| virtual bool | isNonDiff () const |
| Special treatment needed for elastic and diffractive processes. | |
| virtual bool | isResolved () const |
| virtual bool | isDiffA () const |
| virtual bool | isDiffB () const |
| virtual bool | isDiffC () const |
| virtual bool | isSUSY () const |
| Special treatment needed for SUSY processes. | |
| virtual bool | allowNegativeSigma () const |
| Special treatment needed if negative cross sections allowed. | |
| virtual int | id3Mass () const |
| virtual int | id4Mass () const |
| virtual int | id5Mass () const |
| virtual int | resonanceA () const |
| Special treatment needed if process contains an s-channel resonance. | |
| virtual int | resonanceB () const |
| virtual bool | isSChannel () const |
| 2 -> 2 and 2 -> 3 processes only through s-channel exchange. | |
| virtual int | idSChannel () const |
| NOAM: Insert an intermediate resonance in 2 -> 1 -> 2 (or 3) listings. | |
| virtual int | idTchan1 () const |
| Special treatment in 2 -> 3 with two massive propagators. | |
| virtual int | idTchan2 () const |
| virtual double | tChanFracPow1 () const |
| virtual double | tChanFracPow2 () const |
| virtual bool | useMirrorWeight () const |
| virtual int | gmZmode () const |
| Special process-specific gamma*/Z0 choice if >=0 (e.g. f fbar -> H0 Z0). | |
| bool | swappedTU () const |
| Tell whether tHat and uHat are swapped (= same as swap 3 and 4). | |
| int | id (int i) const |
| Give back particle properties: flavours, colours, masses, or all. | |
| int | col (int i) const |
| int | acol (int i) const |
| double | m (int i) const |
| Particle | getParton (int i) const |
| double | Q2Ren () const |
| double | alphaEMRen () const |
| double | alphaSRen () const |
| double | Q2Fac () const |
| double | pdf1 () const |
| double | pdf2 () const |
| double | thetaMPI () const |
| Give back angles; relevant only for multipe-interactions processes. | |
| double | phiMPI () const |
| double | sHBetaMPI () const |
| double | pT2MPI () const |
| double | pTMPIFin () const |
| void | saveKin () |
| Save and load kinematics for trial interactions. | |
| void | loadKin () |
| void | swapKin () |
| virtual void | setIdInDiff (int, int) |
| Set the incoming ids for diffraction. | |
| Public Member Functions inherited from PhysicsBase | |
| void | initInfoPtr (Info &infoPtrIn) |
| This function is called from above for physics objects used in a run. More... | |
| virtual | ~PhysicsBase () |
| Empty virtual destructor. | |
| bool | flag (string key) const |
| Shorthand to read settings values. | |
| int | mode (string key) const |
| double | parm (string key) const |
| string | word (string key) const |
| vector< bool > | fvec (string key) const |
| vector< int > | mvec (string key) const |
| vector< double > | pvec (string key) const |
| vector< string > | wvec (string key) const |
Protected Member Functions | |
| void | pickFinal () |
| void | mapFinal () |
| Map a final state configuration. | |
| double | m2Calc () |
| |M|^2 calculation More... | |
| Protected Member Functions inherited from Sigma3Process | |
| Sigma3Process () | |
| Constructor. | |
| virtual void | store3Kin (double x1in, double x2in, double sHin, Vec4 p3cmIn, Vec4 p4cmIn, Vec4 p5cmIn, double m3in, double m4in, double m5in, double runBW3in, double runBW4in, double runBW5in) |
| Store kinematics and set scales for resolved 2 -> 3 process. More... | |
| virtual bool | setupForME () |
| Calculate modified masses and four-vectors for matrix elements. More... | |
| Protected Member Functions inherited from SigmaProcess | |
| SigmaProcess () | |
| Constructor. | |
| void | addBeamA (int idIn) |
| void | addBeamB (int idIn) |
| int | sizeBeamA () const |
| int | sizeBeamB () const |
| void | addPair (int idAIn, int idBIn) |
| int | sizePair () const |
| bool | setupForMEin () |
| Calculate incoming modified masses and four-vectors for matrix elements. More... | |
| void | setId (int id1in=0, int id2in=0, int id3in=0, int id4in=0, int id5in=0) |
| Set flavour, colour and anticolour. | |
| void | setColAcol (int col1=0, int acol1=0, int col2=0, int acol2=0, int col3=0, int acol3=0, int col4=0, int acol4=0, int col5=0, int acol5=0) |
| void | swapColAcol () |
| void | swapCol1234 () |
| void | swapCol12 () |
| void | swapCol34 () |
| double | weightTopDecay (Event &process, int iResBeg, int iResEnd) |
| Common code for top and Higgs secondary decay angular weights. More... | |
| double | weightHiggsDecay (Event &process, int iResBeg, int iResEnd) |
| Protected Member Functions inherited from PhysicsBase | |
| PhysicsBase () | |
| Default constructor. | |
| virtual void | onInitInfoPtr () |
| virtual void | onBeginEvent () |
| This function is called in the very beginning of each Pythia::next call. | |
| virtual void | onEndEvent (Status) |
| virtual void | onStat () |
| This function is called from the Pythia::stat() call. | |
| void | registerSubObject (PhysicsBase &pb) |
| Register a sub object that should have its information in sync with this. | |
Protected Attributes | |
| int | config |
| Pick/map a random final state configuration. | |
| Vec4 | pCM [5] |
| Four-vectors for |M|^2 calculation. | |
| double | a [3] |
| Intermediate storage and calculation of four-products. | |
| double | b [3] |
| double | pp [3][3] |
| double | ab [3][3] |
| double | sigma |
| Values stored for colour flow selection. | |
| Protected Attributes inherited from Sigma3Process | |
| double | m3 |
| Store subprocess kinematics quantities. | |
| double | s3 |
| double | m4 |
| double | s4 |
| double | m5 |
| double | s5 |
| double | runBW3 |
| double | runBW4 |
| double | runBW5 |
| Vec4 | p3cm |
| Vec4 | p4cm |
| Vec4 | p5cm |
| Protected Attributes inherited from SigmaProcess | |
| SusyLesHouches * | slhaPtr |
| Pointer to an SLHA object. | |
| LHAupPtr | lhaUpPtr |
| Pointer to LHAup for generating external events. | |
| bool | doVarE |
| Initialization data, normally only set once. | |
| int | nQuarkIn |
| int | renormScale1 |
| int | renormScale2 |
| int | renormScale3 |
| int | renormScale3VV |
| int | factorScale1 |
| int | factorScale2 |
| int | factorScale3 |
| int | factorScale3VV |
| double | Kfactor |
| double | mcME |
| double | mbME |
| double | mmuME |
| double | mtauME |
| double | renormMultFac |
| double | renormFixScale |
| double | factorMultFac |
| double | factorFixScale |
| int | higgsH1parity |
| CP violation parameters for Higgs sector, normally only set once. | |
| int | higgsH2parity |
| int | higgsA3parity |
| double | higgsH1eta |
| double | higgsH2eta |
| double | higgsA3eta |
| double | higgsH1phi |
| double | higgsH2phi |
| double | higgsA3phi |
| int | idA |
| Information on incoming beams. | |
| int | idB |
| double | mA |
| double | mB |
| bool | isLeptonA |
| bool | isLeptonB |
| bool | hasLeptonBeams |
| bool | beamA2gamma |
| bool | beamB2gamma |
| bool | hasGamma |
| vector< InBeam > | inBeamA |
| Partons in beams, with PDF's. | |
| vector< InBeam > | inBeamB |
| vector< InPair > | inPair |
| Allowed colliding parton pairs, with pdf's. | |
| double | mH |
| Store common subprocess kinematics quantities. | |
| double | sH |
| double | sH2 |
| double | Q2RenSave |
| Store Q2 renormalization and factorization scales, and related values. | |
| double | alpEM |
| double | alpS |
| double | Q2FacSave |
| double | x1Save |
| double | x2Save |
| double | pdf1Save |
| double | pdf2Save |
| double | sigmaSumSave |
| int | id1 |
| Store flavour, colour, anticolour, mass, angles and the whole particle. | |
| int | id2 |
| int | id3 |
| int | id4 |
| int | id5 |
| int | idSave [12] |
| int | colSave [12] |
| int | acolSave [12] |
| double | mSave [12] |
| double | cosTheta |
| double | sinTheta |
| double | phi |
| double | sHMass |
| double | sHBeta |
| double | pT2Mass |
| double | pTFin |
| Particle | parton [12] |
| Particle | partonT [12] |
| double | mSaveT [12] |
| double | pTFinT |
| double | cosThetaT |
| double | sinThetaT |
| double | phiT |
| double | mME [12] |
| Vec4 | pME [12] |
| bool | swapTU |
| Store whether tHat and uHat are swapped (= same as swap 3 and 4). | |
| Protected Attributes inherited from PhysicsBase | |
| Info * | infoPtr = {} |
| Settings * | settingsPtr = {} |
| Pointer to the settings database. | |
| ParticleData * | particleDataPtr = {} |
| Pointer to the particle data table. | |
| Logger * | loggerPtr = {} |
| Pointer to logger. | |
| HadronWidths * | hadronWidthsPtr = {} |
| Pointer to the hadron widths data table. | |
| Rndm * | rndmPtr = {} |
| Pointer to the random number generator. | |
| CoupSM * | coupSMPtr = {} |
| Pointers to SM and SUSY couplings. | |
| CoupSUSY * | coupSUSYPtr = {} |
| BeamSetup * | beamSetupPtr = {} |
| BeamParticle * | beamAPtr = {} |
| BeamParticle * | beamBPtr = {} |
| BeamParticle * | beamPomAPtr = {} |
| BeamParticle * | beamPomBPtr = {} |
| BeamParticle * | beamGamAPtr = {} |
| BeamParticle * | beamGamBPtr = {} |
| BeamParticle * | beamVMDAPtr = {} |
| BeamParticle * | beamVMDBPtr = {} |
| PartonSystems * | partonSystemsPtr = {} |
| Pointer to information on subcollision parton locations. | |
| SigmaTotal * | sigmaTotPtr = {} |
| Pointers to the total/elastic/diffractive cross sections. | |
| SigmaCombined * | sigmaCmbPtr = {} |
| set< PhysicsBase * > | subObjects |
| UserHooksPtr | userHooksPtr |
Additional Inherited Members | |
| Public Types inherited from PhysicsBase | |
| enum | Status { INCOMPLETE = -1, COMPLETE = 0, CONSTRUCTOR_FAILED, INIT_FAILED, LHEF_END, LOWENERGY_FAILED, PROCESSLEVEL_FAILED, PROCESSLEVEL_USERVETO, MERGING_FAILED, PARTONLEVEL_FAILED, PARTONLEVEL_USERVETO, HADRONLEVEL_FAILED, CHECK_FAILED, OTHER_UNPHYSICAL, HEAVYION_FAILED, HADRONLEVEL_USERVETO } |
| Enumerate the different status codes the event generation can have. | |
| Public Attributes inherited from SigmaProcess | |
| Z0 gamma *Z0 * | Usage: weightDecayFlav( process). */ virtual double weightDecayFlav( Event&) {return 1. |
| Static Protected Attributes inherited from SigmaProcess | |
| static const double | CONVERT2MB = 0.389380 |
| Constants: could only be changed in the code itself. More... | |
| static const double | MASSMARGIN = 0.1 |
| The sum of outgoing masses must not be too close to the cm energy. | |
| static const double | COMPRELERR = 1e-10 |
| static const int | NCOMPSTEP = 10 |
A derived class for q qbar -> g g g.
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inlineprotected |
|M|^2 calculation
|M|^2
Calculate four-products
qbar (p+) + q(p-) -> g(k1) g(k2) g(k3) a_i = (p+ . ki), i = 1, 2, 3 b_i = (p- . ki), i = 1, 2, 3
ab[i][j] = a_i * b_j + a_j * b_i
Cross section
Final answer
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virtual |
Select flavour, colour and anticolour.
Select identity, colour and anticolour.
Flavours are trivial.
Temporary solution.
Reimplemented from SigmaProcess.
Reimplemented in Sigma3gg2qqbarg, and Sigma3qg2qgg.
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virtual |
Calculate flavour-independent parts of cross section.
Evaluate |M|^2 - no incoming flavour dependence.
Sigma3qqbar2ggg class. Cross section for q qbar -> g g g.
Setup four-vectors
Calculate |M|^2 Answer has a factor 6 due to identical gluons, which is cancelled by phase space factor (1 / 6)
Reimplemented from SigmaProcess.
Reimplemented in Sigma3gg2qqbarg, and Sigma3qg2qgg.
1.8.11
