sci-physics ROOT Object Oriented Technologies is an object oriented data analysis framework written in C++ by the CERN. Widely used in high energy physics, but also in other data analysis applications. It contains the CINT C/C++ interpreter and many classes such as statistics, serialization, optimization, linear algebra, graphics, GUI toolkit, and a complete visualization framework. Build the HBOOK input/ouput functionality. HBOOK is a histogram library. On ROOT versions previous to 5.20.00, it will depend on sci-physics/cernlib. On versions above, it only need a FORTRAN compiler. Buld the Clarens and PEAC plug-ins, to use in a GRID enabled analysis. The Clarens Grid-Enabled Web Services Framework is an open source portal for ubiquitous access to data and computational resources provided by computing grids. PEAC is an interactive distributed analysis framework that uses Clarens as a glue protocol to advertise and communicate amongst SAM, Global Manager (GM), Local Manager (LM), DCache, and PROOF services. It doesn't need Clarens to build, however if you want to use it, you will require to build Clarens and PEAC on your own, it is not yet in the Gentoo Portage tree. See http://clarens.sourceforge.net/ for Clarens and http://physics.ucsd.edu/~schsu/project/peac.html for PEAC. Build the sci-physics/geant (GEANT4) navigator. Build all math libraries plugins. It includes the sci-libs/gsl bindings in MathMore, the GenVector physical vectors package, the Minuit2 minimization library (same as standalone sci-libs/minuit), the RooFit toolkit for distribution modeling, and the Universal Non-Uniform RANdom number generators (UNURAN) library. Builds the interface to Pythia-6 (sci-physics/pythia) high energy physics generation events library. Builds the interface to Pythia-8 (sci-physics/pythia) high energy physics generation events library. Builds the reflection database for the C++ interpretor. Build the xrootd low latency file server. For more on the eXtended Request Daemon (xrd) and associated software, please see http://xrootd.slac.stanford.edu.