WLCG is a global collaboration of more than 170 computing centres in 42 countries, linking up national and international grid infrastructures. The mission is to provide global computing resources to store, distribute and analyse the data generated by the High Energy Physics experiments hosted by the Large Hadron Collider (LHC) at CERN.
The observations collected by the LHC detectors generate an enormous amount of data that needs to be stored, distributed across hundreds of scientific institutions worldwide and then analysed by thousands of scientists. This regularly involves data transfers of +80 Petabytes / month and ~700 million computing jobs / year, which consume about 5 billion CPU hours.
The services provided by the EGI Federation are essential to run a global exascale, distributed computing infrastructure such as WLCG. The collaboration between WLCG and what is now EGI is over 10 years old: WLCG has been involved in every step of the development of EGI and is the biggest consumer of EGI compute resources. The four largest EGI Virtual Organi-sations are all LHC experiments: ATLAS, ALICE, CMS and LHCb.
The computing is in itself an achievement, but the scientific results also endorse the approach. WLCG managed the computational challenges that led, for example, to the discovery of the Higgs Boson in 2012 by ATLAS and CMS, or the LHCb discovery of ‘charmonium particles’ earlier in 2017.