The Particle Physics Data Grid collaboration was formed in 1999 because its members were keenly aware of the need for Data Grid services to enable the worldwide distributed computing model of current and future high-energy and nuclear physics experiments. Initially funded from the NGI initiative and later from the DOE MICS and HENP programs, it has provided an opportunity for early development of the Data Grid architecture as well as evaluating some prototype Grid middleware.

With the current SciDAC project (Particle Physics Data Grid Collaboratory Pilot), PPDG will develop, acquire and deliver vitally needed Grid-enabled tools for data-intensive requirements of particle and nuclear physics. Novel mechanisms and policies will be vertically integrated with Grid middleware and experiment-specific applications and computing resources to form effective end-to-end capabilities. PPDG is a collaboration of computer scientists with a strong record in distributed computing and Grid technology, and physicists with leading roles in the software and network infrastructures for major high-energy and nuclear experiments. Together they have the experience, knowledge and vision in the scientific disciplines and technologies required to bring Grid-enabled data manipulation and analysis capabilities to the desk of every physicist. We have outlined a three-year program taking full advantage of the strong driving force provided by now running physics experiments, ongoing Computer Science projects and recent advances in Grid technology. Our goals and plans are ultimately guided by the immediate, medium-term and longer-term needs and perspectives of the physics experiments, some of which will run for at least a decade from 2006 and by the research and development agenda of the CS projects involved in PPDG and other Grid-oriented efforts. 

PPDG is actively participating in iVDGL together with GriPhyN as a three prong approach to data grids for US physics experiments, symbolized by Trillium flower.  As well, it is working closely with complementary data grid initiatives in Europe and beyond: GlobalGridForum, European DataGrid and as part of the HENP InterGrid Coordination Board (HICB) and HICB Joint Technical Board.