Welcome to Test4Theory (also known as "Virtual LHC@home" or "LHC@home 2.0" according to the evolutions of our technology!)
The Test4Theory project allows volunteers to run simulations of high energy particle collisions on their home computers. These simulations use theoretical models based on the Standard Model of particle physics, and are calculated using Monte Carlo methods. The theoretical models have adjustable parameters and the aim is that a given set of parameters (called a "tune") will fit the widest possible range of experimental results.
The Test4Theory results are therefore submitted to a database which contains a very wide set of experimental data from many accelerator experiments worldwide, including of course experiments at the Large Hadron Collider at CERN. The database and the theoretical fitting process is part of the project MCPLots, based in the Theory Unit at CERN.