Glossary
 
 
 
 
- BR
- Beam Remnants; not much used since it may be confused with 
Branching Ratio; sometimes called beam-beam remnants, BBR
- BSM
- Beyond-the-Standard-Model physics, as a generic term for anything 
not contained within the SM
- CR
- Colour Reconnection
- FSR
- Final-State Radiation, implemented in terms of timelike showers
- LHA
- Les Houches Accord for user processes, describing which process-level 
information should be stored to allow further showering and hadronization 
of "skeleton" hard processes
- LHAPDF
- Les Houches Accord Parton Distribution Functions, originally a standard 
format for defining PDF's and later a library with such PDF's
- LHEF
- Les Houches Event File(s), a file format for storing LHA process and 
event information
- ISR
- Initial-State Radiation, implemented in terms of spacelike showers
- MPI
- Multiparton Interactions, i.e. several (more or less) independent 
parton-parton subcollisions as part of a hadron-hadron event (previously 
called MI for multiple interactions)
- MSSM
- Minimal Supersymmetric extension of the Standard Model
- PDF
- Parton Distribution Function (alternatively Parton Density 
Function)
- PDG code
- a scheme for assigning unique integers, particle identity codes, 
to known and hypothetical particles; code rules and tables are published 
in the RPP (see below).
- pileup
- several hadron-hadron collisions in a bunch crossing; not to 
be confused with MPI
- RPP
- Review of Particle Physics, the biannual review by the ParticleData Group 
(PDG) from which many Standard-Model parameter values and much particle data 
has been taken (but, given the poor data on many hadron resonances, a lot of 
extra (guess)work is needed)
- setting
- collectively used to denote all the boolean flag, 
integermode, double-precisionparmand stringwordvariables that can be set by the user 
to steer the behaviour of a run; normally particle data are considered 
separately but clearly are closely related
- SLHA
- SUSY Les Houches Accord for interchange of mass and coupling information 
in SUSY scenarios, via a well-defined file format
- SM
- the Standard Model of particle physics
- SUSY
- SUperSYmmetry
- units
- Normal PYTHIA input, internal operations and output is based on a set of 
standard units, such as: 
 GeV for all energies, momenta and masses, always with c = 1;
 mm for all distances and mm/c for all times, 
so that again they match for c = 1;
 mb for all cross sections (but input or output via the Les Houches 
Accord takes into account that the unit there is pb)