CNAF hosts the Italian Tier-1 site, one of the eleven Tier-1 centers of the Worldwide LHC Computing Grid, which builds and maintains data storage and analysis infrastructure for the international high energy physics community using the Large Hadron Collider (LHC) at CERN in Geneva.

One of the main functions of the Tier-1 centers is to get in real time a share of the raw data taken by the experiments, and provide long-term storage for it. Of course, at CNAF data are not only stored, but also processed to generate calibrated and filtered data, which then can be transferred to Tier-2 sites and researchers worldwide. Acting as a Tier-1 center, CNAF provides both resources and expertise to the four LHC experiments

whose particle detectors are located in huge caverns underground on the LHC ring, and record and analyse the myriad of particles produced by collisions in the accelerator. These experiments, run by collaborations of scientists from institutes all over the world, investigate a wide range of high energy physics, from the search for the Higgs boson and standard model studies to extra-dimensions and particles that could make up dark matter.

LHC experiments represent the main users of CNAF facilities: they heavily use Grid technologies, on top of which they have built experiment specific services to support data management, job management and monitoring in a better way. However, CNAF also supports the computing communities of an increasing number of experiments, mostly dedicated to astro-particle and neutrino-physics. In particular, CNAF provides (or has provided) computing facilities and expertise to the following experiments: