Frank Close, an Oxford physicist, explains the purpose of the Large Hadron Collider:
We're creating in the laboratory the conditions that the universe experienced about a trillionth of a second after the big bang. There are observations that have taken us to a billionth of a second after the big bang, so we've been pretty near. You might think, "Oh, why would we want to get nearer?" It's because the stuff that you and I are made of was created in that cauldron of the big bang's aftermath, and there are puzzles yet to be solved. For example, why is anything left today?
Antimatter is real, and matter and antimatter annihilate when they meet. So why didn't the newborn universe annihilate itself after the big bang. There must be something that tipped the balance. What that is, we don't know for sure, but some hints are beginning to emerge from the Large Hadron Collider.