PROGRAM SUMMARY
Title of program:
KK version 4.12
Catalogue identifier:
ADMD
Ref. in CPC:
130(2000)260
Distribution format: tar gzip file
Operating system: UNIX, AIX 4.x, HP-UX 10.x, Linux
High speed store required:
10MK words
Number of lines in distributed program, including test data, etc:
367940
Keywords:
Particle physics, Elementary, Electrodynamics quantum, Standard model,
Electroweak interactions, Heavy boson Z, Spin polarization,
Spin correlations, Radiative corrections, Initial-state radiation,
Final-state radiation, interference QED, Monte Carlo simulation
and generation, Coherent exclusive exponentiation (CEEX),
Yennie-Frautschi-Suura exponentiation, LEP2, Linear collider,
TESLA, Event simulation.
Programming language used: Fortran
Computer:
IBM PowerPC M43P240 .
Nature of physical problem:
The fermion pair production is and will be used as an important data
point for precise tests of the standard electroweak theory at LEP and
future linear colliders at higher energies. QED corrections to fermion
pair production (especially tau leptons) at c-quark and b-quark
factories has to be known to second order, including spin polarization
effects. The Standard Model predictions at the per mille precision
level, taking into account multiple emission of photons for realistic
experimental acceptance, can only be obtained using a Monte Carlo event
generator.
Method of solution
The Monte Carlo methods are used to simulate most of the two-fermion
final-state processes in e+e- collisions in the presence of multiphoton
initial-state radiation. The latter is described in the framework of
exclusive coherent exponentiation (CEEX) based on Yennie-Frautschi-Suura
exclusive exponentiation (YFS/EEX). CEEX treats correctly to infinite
order not only infrared cancellations but also QED interferences and
narrow resonances. The matrix element according to standard YFS
exponentiation is also provided for tests. For quarks and tau leptons,
the appropriate simulation of hadronization or decay is included. Beam
polarization and spin effects, both longitudinal and transverse, in tau
decays are properly taken into account.
Restrictions on the complexity of the problem
In the present version, electron (Bhabha), neutrino and top quark final
states are not included (they will be in a future version). Additional
fermion pair production is not included. Third-order QED corrections in
leading-logarithmic approximation are included only in the auxiliary
YFS/EEX matrix element (which can be activated with the help of input
parameters). Electroweak corrections should not be trusted above the
t-quark threshold. The total cross section for light quarks for
sqrt(s)<10 GeV requires an improvement using experimental data.
Typical running time
On the IBM PowerPC M43P240 installation (266 MHz, 65 CERN units) 4 sec
per constant-weight event are needed. This result is for a
default/recommended setting of the input parameters, with all
hadronization/decay libraries switched ON.