For the numerical evaluation of
hadronic cross sections I have developed a program called
HadCalc to facilitate this task. It
is based on the established program packages
FeynArts and
FormCalc which are used to
generate the partonic cross sections. The main task of HadCalc then
consists of the convolution with the PDFs that are taken from the
PDFlib or
LHAPDF library
packages that include PDF fits from various groups.
With this program it is possible to
calculate both totally integrated and differential hadronic cross
sections of processes with up to three particles in the final
state. The latter ones can be differential with respect to the
partonic center-of-mass energy, or the rapidity or the transverse
momentum of one of the outgoing particles. Several cuts can be applied
to the phase space. HadCalc operates either in batch mode, where the
parameters are read from a file and the cross sections are written back
to disk, allowing for easy post-processing with e.g. a tool that
generates plots. It can also be used in interactive mode where in- and
output are done via keyboard and screen and which allows the user for
example to tune the parameters most easily.
Download
Installation
To use HadCalc first generate your process with FeynArts and FormCalc.
If you still use the older FormCalc with a version number starting with
4, then there is nothing else you would need at this stage. If you use
the newer FormCalc version 5, then you additionally need the
drivers.tar.gz package. Unpack it with
tar -xzvf
drivers.tar.gz. At the end of FormCalc, when writing the
generated amplitudes to a file, specify the directory with the unpacked
drivers as an argument to
SetupCodeDir, as in
[...]
dir = SetupCodeDir["partondir", Drivers ->
"/path/to/unpacked/drivers"];
WriteSquaredME[ born, {}, Abbr[], dir];
[...]
In all cases, change into the generated directory, adapt process.h
according to the FormCalc manual and run
./configure.
Unpack HadCalc.tar.gz in any directory, change into this directory and
run
./configure with the appropriate arguments (see the
HadCalc manual for details), followed by
gmake.
After that you are finished. Run
./HadCalc and follow the
on-screen instructions, or read the manual for further options.
Reference
The development of HadCalc was part of my PhD thesis. If you like it,
please cite the following reference:
%\cite{Rauch:2008fy}
\bibitem{Rauch:2008fy}
M.~Rauch,
%``Quantum Effects in Higgs-Boson Production Processes at Hadron
Colliders,''
arXiv:0804.2428 [hep-ph].
%%CITATION = ARXIV:0804.2428;%% |
