First Step Instructions

This documentation briefly summarizes the first steps on how to install and compile the PANDA PWA software and how to run some test applications.

Note: Up to now there is only rudimentary code available and thus it is generally not yet possible to perform PWA's.

Required compiler version: gcc >= 4.1.2

Software Repository and Access to the Source Code

The software source code is available via git. You can have a look to the repository using your browser at http://www.ep1.rub.de/git/gitweb.cgi by clicking on "Pawian". In order to check out and commit code you have to install git. Some useful information and instructions can be found here.

You can make your first clone of the repository by typing:

git clone gitosis@tau.ep1.rub.de:/var/www/git/Pawian

A new directory "Pawian" will be created on your local machine containing the source code and the cmake steering files.

External Packages

Before you can compile and link the code the following external packages must be installed:

• bjam
• ROOT
• Boost (at least version 1.48.0)
• log4cpp
• Minuit2
• GenEvA (version 0.9.1)
• HepMC (version 2.04.02)

You can download the source code or the relevant tar-files for

• Boost from http://www.boost.org/
• log4cpp from http://www.ep1.rub.de/PWA/log4cpp-1.0.tar.gz
• GenEvA from https://launchpad.net/geneva
• Minuit2 from http://www.ep1.rub.de/PWA/Minuit2.tar.gz
• HepMC from http://lcgapp.cern.ch/project/simu/HepMC/download

If the packages are installed you have to modify the file "site-config.jam" which is available in your BOOST_BUILD_PATH. Here you should define all standard-paths of the external packages. Then you have to set the environment variables ROOTSYS, LD_LIBRARY_PATH, PATH, BOOST_BUILD_PATH and CMAKE_SOURCE_DIR. An Example can be found in the top-directory of the PAWIAN package where the Env-variables are defined for the RUB-installation. The last step, before you are able to compile and link, is to check whether all paths are correct in the file "Jamroot". The "Jamroot"-file is also available in the top directory.

Compilation and Linking

Now you are ready for compiling and linking the code.. By typing

• "bjam" executables with debugging options will be created. These executables and the relevant libraries are then located at "subdirectory"/bin//debug/link-static/
• "bjam release" executables with optimized performance will be created. Here you can find the relevant executables in "subdirectory"/bin//release/link-static/

By typing "bjam clean" or "bjam release clean" you clean up your created executables and libraries and you can start to compile the code from scratch.

Starting the Test Applications

• SeqDecayHeliAmpsApp : this very simple application makes use of the qft++ tool. It reads in phasespace distributed π⁰π⁰η events, calculates the contributed amplitudes in the helicity formalism for the sequential decay mother -> inter π⁰, where inter -> π⁰ η, and creates dalitz plots and histograms with the weighted invariant masses and angular distributions. The intermediate resonance will be taken into acccount with a simple Breit-Wigner function (m=1.320 GeV, sigma(m)=0.100 GeV). To get detailed instructions how to start this application, simply type: ./SeqDecayHeliAmpsApp --help

• PdtTestApp : this test application reads in an input pdt-table, creates a particle table object which will be cloned and modified. In addition some particles are extracted and asked for specific properties.

• MEtacToapi0fitApp : this is a simple PWA fit for the decay chain η_c->(inter) π⁰->(π⁰ η) π⁰. It makes use of the qft++ tool and Minuit2 and calculates the amplitude in the Covariant Tensor Formalism. The fit determines whether the intermediate resonance is a spin 0,1 or 2 particle. In addition the mass and width of the intermediate resonance will be fitted with a simple Breit-Wigner. You can start the application with (faked) data containing the a₂(1320) as an intermediate resonance by typing: MEtacToapi0fitApp -d 2. Then you will get the fit result as follows:
  • mass = 1.308 GeV (start value 1.6 GeV)
  • width= 0.114 GeV (start value 0.04 GeV)
  • spin 0 content = 3.24e-08 (start value 0.3)
  • spin 1 content = 0.00493972 (start value 0.3)
  • spin 2 content =0.999998 (start value 0.3)

The histogram shows the invariant π⁰ η mass for the data (red), phase space distributed Monte Carlo events (blue) and Monte Carlo events weighted with the resulting fit parameters (black). You can also fit data containing the a₀(980) as an intermediate resonance. For this, simply type: MEtacToapi0fitApp -d 0

• GEtacToapi0fitApp : this application performs the same PWA fit as MEtacToapi0fitApp. The only difference is that it makes use of the minimizer Geneva instead of Minuit2. You can start the application by typing: ./GEtacToapi0FitApp -c $CMAKE_SOURCE_DIR/Examples/EtacToapi0Fit/GEtacToapi0FitProject.cfg . You can run the minimization procedure either in the serial, multi-threaded or networked (2) mode.

-- BertramKopf - 07 May 2010