Welcome to the Large Hadron Collider

Tunnelling to the beginning of time

The LHC (Large Hadron Collider) is an international project, in which the UK has a leading role. This site includes the latest news from the project, accessible explanations of how the LHC works, how it is funded, who works there and what benefits it brings us. You can access a wide range of resources for the public, journalists and teachers and students, there are also many links to other sources of information.

The LHC is asking some Big Questions about the universe we live in

1) How did our universe come to be the way it is?

The Universe started with a Big Bang – but we don’t fully understand how or why it developed the way it did. The LHC will let us see how matter behaved a tiny fraction of a second after the Big Bang. Researchers have some ideas of what to expect – but also expect the unexpected!

2) What kind of Universe do we live in?

Many physicists think the Universe has more dimensions than the four (space and time) we are aware of. Will the LHC bring us evidence of new dimensions?
Gravity does not fit comfortably into the current descriptions of forces used by physicists. It is also very much weaker than the other forces. One explanation for this may be that our Universe is part of a larger multi dimensional reality and that gravity can leak into other dimensions, making it appear weaker. The LHC may allow us to see evidence of these extra dimensions - for example, the production of mini-black holes which blink into and out of existence in a tiny fraction of a second.

3) What happened in the Big Bang?

What was the Universe made of before the matter we see around us formed? The LHC will recreate, on a micro scale, conditions that existed during the first billionth of a second of the Big Bang.

At the earliest moments of the Big Bang, the Universe consisted of a searingly hot soup of fundamental particles - quarks, leptons and the force carriers. As the Universe cooled to 1000 billion degrees, the quarks and gluons (carriers of the strong force) combined into composite particles like protons and neutrons. The LHC will collide lead nuclei so that they release their constituent quarks in a fleeting ‘Little Bang’. This will take us back to the time before these particles formed, re-creating the conditions early in the evolution of the universe, when quarks and gluons were free to mix without combining. The debris detected will provide important information about this very early state of matter.

4) Where is the antimatter?

The Big Bang created equal amounts of matter and antimatter, but we only see matter now. What happened to the antimatter?
Every fundamental matter particle has an antimatter partner with equal but opposite properties such as electric charge (for example, the negative electron has a positive antimatter partner called the positron). Equal amounts of matter and antimatter were created in the Big Bang, but antimatter then disappeared. So what happened to it? Experiments have already shown that some matter particles decay at different rates from their anti-particles, which could explain this. One of the LHC experiments will study these subtle differences between matter and antimatter particles.

5) Why do particles have mass?

Why do some particles have mass while others don’t? What makes this difference? If the LHC reveal particles predicted by theory it will help us understand this.
Particles of light (known as photons) have no mass. Matter particles (such as electrons and quarks) do – and we’re not sure why. British physicist, Peter Higgs, proposed the existence of a field (the Higg’s Field), which pervades the entire Universe and interacts with some particles and this gives them mass. If the theory is right then the field should reveal itself as a particle (the Higg’s particle). The Higg’s particle is too heavy to be made in existing accelerators, but the high energies of the LHC should enable us to produce and detect it.

6) What is our Universe made of?

Ninety-six percent of our Universe is missing! Much of the missing matter is stuff researchers have called ‘dark matter’. Can the LHC find out what it is made of?
The theory of ‘supersymmetry’ suggests that all known particles have, as yet undetected, ‘superpartners’. If they exist, the LHC should find them. These ‘supersymmetric’ particles may help explain one mystery of the Universe – missing matter. Astronomers detect the gravitational effects of large amounts of matter that can’t be seen and so is called ‘Dark Matter’. One possible explanation of dark matter is that it consists of supersymmetric particles.