FeynArts (Popularity: ): Mathematica package for generation and visualization of Feynman diagrams and amplitudes. Phi (Phenomenology of Hadronic Interactions) (Popularity: ): Extension of the Mathematica packages, FeynCalc and FeynArts. FeynCalc (Popularity: ): Mathematica package for algebraic calculations in elementary particle physics, focusing on Feynman diagram calculations. The ROOT System (Popularity: ): An object oriented framework for large scale data analysis. ROOT is a C++ replacement of the popular PAW program developed at CERN. cfortran.h - Interfacing C/C++ and FORTRAN (Popularity: ): cfortran.h is a single header file that allows you to easily use fortran code in c and c++. Very useful for using HBOOK and other CERNLIB code in new c++ ... Texsis - TeX Macros for Physicists (Popularity: ): This package provides a number of useful features for typesetting research papers. It is an extension to Plain Tex. FLUKA (Fluktuierende Kaskade) (Popularity: ): A stand-alone particle physics Monte-Carlo simulation package. It is being used as a simulation tool in a number of experiments. Fermitools (Popularity: ): The Fermilab Software Tools Program (Fermitools) aims to provide useful tools to the community. A wide range of tools are available, and all are free. PYTHIA (and JETSET) (Popularity: ): An event generator for a large number of physics processes. The site contains the latest source, the official manual and a short write-up describing PYTHIA's status with respect to the ... Pandora (Popularity: ): A physics event generator for linear collider studies. It includes beamstrahlung, initial state radiation, hadronization, and full treatment of polarization effects.