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PYTHIA
8.311
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#include <MultipartonInteractions.h>
Public Member Functions | |
| SigmaMultiparton () | |
| Constructor. | |
| bool | init (int inState, int processLevel, Info *infoPtr, BeamParticle *beamAPtr, BeamParticle *beamBPtr) |
| Initialize list of processes. More... | |
| void | updateBeamIDs () |
| Switch to new beam particle identities. | |
| double | sigma (int id1, int id2, double x1, double x2, double sHat, double tHat, double uHat, double alpS, double alpEM, bool restore=false, bool pickOtherIn=false) |
| Calculate cross section summed over possibilities. More... | |
| bool | pickedOther () |
| Return whether the other, rare processes were selected. | |
| SigmaProcessPtr | sigmaSel () |
| Return one subprocess, picked according to relative cross sections. More... | |
| bool | swapTU () |
| int | nProc () const |
| Return code or name of a specified process, for statistics table. | |
| int | codeProc (int iProc) const |
| string | nameProc (int iProc) const |
SigmaMultiparton is a helper class to MultipartonInteractions. It packs pointers to the allowed processes for different flavour combinations and levels of ambition.
| bool init | ( | int | inState, |
| int | processLevel, | ||
| Info * | infoPtr, | ||
| BeamParticle * | beamAPtr, | ||
| BeamParticle * | beamBPtr | ||
| ) |
Initialize list of processes.
Initialize the generation process for given beams.
Store input pointer for future use.
Reset vector sizes (necessary in case of re-initialization).
Always store mimimal set of processes:QCD 2 -> 2 t-channel.
Gluon-gluon instate.
Quark-gluon instate.
Quark-(anti)quark instate.
Normally store QCD processes to new flavour.
Optionally store electroweak processes, mainly photon production.
Optionally store charmonium and bottomonium production.
Resize arrays to match sizes above.
Initialize the processes.
Prepare for massive kinematics where required.
Prepare for (narrow) Breit-Wigner mass distribution.
Done.
| double sigma | ( | int | id1, |
| int | id2, | ||
| double | x1, | ||
| double | x2, | ||
| double | sHat, | ||
| double | tHat, | ||
| double | uHat, | ||
| double | alpS, | ||
| double | alpEM, | ||
| bool | restore = false, |
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| bool | pickOtherIn = false |
||
| ) |
Calculate cross section summed over possibilities.
Choose either the dominant process (in slot 0) or the rest of them.
Iterate over all subprocesses.
Skip the not chosen processes.
Check if variable mass is needed (and then ...Fix becomes misleading).
Check that invariant mass sufficiently large for product masses.
t-channel-sampling contribution.
Correction factor for tHat rescaling in massive kinematics.
u-channel-sampling contribution.
Correction factor for tHat rescaling in massive kinematics.
Average of t- and u-channel sampling; corrected for not selected channels.
| SigmaProcessPtr sigmaSel | ( | ) |
Return one subprocess, picked according to relative cross sections.
Decide between t- and u-channel-sampled kinematics.
Pick one of t-channel-sampled processes.
Pick one of u-channel-sampled processes.
1.8.11
