The VINCIA code is a shower plugin to the high-energy physics event generator PYTHIA 8. It is based on the dipole-antenna picture of Quantum Chromodynamics (QCD) and focusses on describing quark and gluon radiation with high precision. It is currently implemented for QCD final-state showers and includes helicity dependence, for massless partons, and mass corrections, for massive ones. Tree-level full-color matrix elements can be automatically incorporated and are then re-interpreted as process-dependent 2→n antenna functions. In hard parts of phase space, these functions generate tree-level matrix-element corrections to the shower. In soft parts, they should improve the logarithmic accuracy of it. Due to the Markovian nature of VINCIA's matching scheme, very high orders of matching can be achieved with only a modest increase in calculational time per event (and zero initialization time). VINCIA also has extensive possibilities for estimating the remaining uncertainties by systematic variations of shower functions, evolution variables, etc. In the automated mode, a vector of output weights is produced for each event, the central value of which is unity (corresponding to an ordinary unweighted event sample), with the uncertainty variations spreading out around it. When activated, VINCIA replaces the internal PYTHIA parton cascades. Hadronization is performed as usual in PYTHIA, with the Lund string fragmentation model. The rest of the run proceeds as a normal PYTHIA 8 run, i.e., using the same functions to initialize, generate, and store events as usual. A runtime display is also available. |
This documentation contains brief descriptions of each of the user-specifiable parameters of the VINCIA code, together with instructions how to install, link, and initialize it. Use the menu to the left to navigate. These files are purely for documentation and should not be modified by the user. Instead, see the section on Initialization for how to set and change parameters.
As in PYTHIA 8, there are 4 types of parameters:
flag
: boolean. Several input forms are accepted:
either of
on
/off
,
true
/false
,
yes
/no
, or 1
/0
will do. mode
: integerparm
: real number (double precision)word
: text stringTo ensure accurate reproducibility, when quoting VINCIA results, please state both the exact PYTHIA and VINCIA versions used, along with any relevant non-default settings (for both programs). On plots, please give both PYTHIA and VINCIA versions.
VINCIA relies on PYTHIA 8 for both technical aspects (everything from four-vectors and the event record to its particle and settings database structures) and physics (e.g., particle decays and hadronization). When citing the VINCIA code, please respect the work of the PYTHIA authors by including a reference to PYTHIA as well, see the section on useful references.
The name VINCIA stands for "VIrtual Numerical Collider with Interleaved Antennae". With roots in PYTHIA, which is a name taken from the ancient greek mythology, the naming of VINCIA is also intended to carry an allusion to the name of Leonardo da Vinci, as a representative of creativity and science in the renaissance era. The logo of VINCIA is the "Vitruvian Man", by da Vinci, a choice which also reflects the combination of art and accuracy which is necessary to write a good event generator.
VINCIA is licenced under the GNU GPL version 2. Please respect the MCnet Guidelines for Event Generator Authors and Users.