GR@PPA --GRace At Proton Proton and proton Anti-proton collisions

News

• [Jul.2005] Bug fixed in bottom flavor PDF. Add QCD 4 jets.


• [Jun.2005] Update versions. Nothing was not changed, but more simplified kinematic routines.


• [Oct.2004] First release of a newly developed general purpose event generator for hadron collisions based on GRACE system. The previous release of our work can be found in GR@PPA_4b which include a full bbbb calculation in SM.

Resources

How to install/run

This program works on Unix/Linux systems. After downloading the "Frame of GR@PPA" (top of this page), on your working directory,

~% tar xzvf GR@PPA-2.76.tgz

Install the "Matrix Element" that you want to use. For example, let's install "W + 1 jet" and "W + 2 jets" processes at the same time. Again, download those sources of the matrix elements from the above. Then,

~% cd GR@PPA-2.76/
~% tar xzvf matrix_w1j_v1.03.tgz
~% tar xzvf matrix_w2j_v1.03.tgz

Type "Config.perl", which is the configuration script to set up the Makefile and kinematics and so on.

~% Config.perl

You will see that your processes of "W + 1 jet" and "W + 2 jets" are correctly configured. If you met any error messages, check the proc.list in top directory of "GR@PPA-2.76/" whether the downloaded Matrix Elements are really included in this proc.list. If not, this version of the GR@PPA frame does not correspond to those processes. In this case, please update the "Frame of GR@PPA" to the newer one.

Edit "Makefile" in top directory of "GR@PPA-2.76/". If you use PDF library or showering Monte Carlo of PYTHIA or HERWIG, point out the locations in "Makefile". Also, you may want to change the compiler (and options) although the "Config.perl" script looks for the location of the compilers.

Also, check the "inc/define.h" to use PDF library and the output (unweighted) event data format. The default settings are to use PYTHIA-PDF which is already hardcoded in the PYTHIA source, and LHA format(hep-hp/0109068) which was proposed on Les Houches 2001 WS. We also have an old style data format which is only available to use PYTHIA.6.1, but it is obsolete.

After editting the "Makefile" and "inc/define.h", compile your matrix elements at first.

~% make w1j
~% make w2j

Then, compile "BASES/SPRING" integration library, "chanel library, and kinematic library.

~% make integ
~% make kinem

Install those library into "GR@PPA-2.76/lib/" directory.

~% make install

The command "make example" makes the Makefiles in each "GR@PPA-2.76/example/". If you want to use PYTHIA, the example program can be found in "GR@PPA-2.76/example/pythia/" directory.

~% make example
~% cd example/pythia/

Finally, select the process identification number (LPRUP(1)) according to the LHA format in "upinit.F". In this case, we need to set 101 for "W + 1 jet" or 102 for "W + 2 jets". The beam energy or kinematical cuts are controlled in this file. The other parameters related to the process specific parameters are set in "grcpar.F". All details about the parameters are described in our paper (in preparetion) and GR@PPA_All Online Manual for v2.65.

The main program is pysample.F when we use PYTHIA, which just produces 100 events. Then, make and run it.

~% make
~% ./pysample

Note that once you make the integration files after the numerical integration with the option "IBSWRT = 0", you need not to make this file again when you make the unweighted events again with the same parameters.

Bench mark cross section