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Getting intense with Project X

Part two of our look at the big particle physics projects that will serve as the successors to the mighty Large Hadron Collider

Before Europe’s Large Hadron Collider stole its crown, America’s Tevatron was the daddy of all particle accelerators. Built at America’s version of CERN, Fermilab, Tevatron spent more than 25 years smashing bunches of protons and antiprotons together. In the process it allowed us to gaze through the wonderful world of the very small and into the bizarre and baffling world of the infinitesimally tiny bits and bobs from which the very small are constructed.

But, in September this year, with its baton securely passed to the LHC, Tevatron was switched off for good. Now physicists are looking for its replacement.

They won’t be looking to out-large the Large Hadron Collider but instead will build a machine capable of mopping up the mess of questions that will come spilling out of the LHC. To do this, the machine will operate at what physicists call the ‘intensity frontier’.

The LHC dominates what is called the ‘energy frontier.’ It is a blunderbuss that uses massive firepower to crash large particles (protons) together and uses detectors the size of cathedrals to pick through the ensuing cloud of debris.

[Graphic: The building blocks of the universe: Electrons, quarks and muons, oh my! Meet the elementary particles. Click to view]

Project X won’t be able to boast anywhere near the LHC’s firepower, but will instead generate incredibly intense beams of particles in the hope that more particles will equal more results. The device will generate a stream of muons – the electron’s bloated cousin – and then use a combination of magnets and superconducting cavities to concentrate the particles into a super-dense, laser-like beam. Unlike the protons, which are bags of smaller particles, that the LHC flings around, muons are ‘fundamental’ particles, which are as small as anything can get.

By smashing together particles that aren’t made up of anything smaller, Project X would avoid the ‘mess’ that the LHC creates. A muon collider would be like a particle physicist’s set of binoculars – zooming in and providing a clear, unobstructed view of the subatomic world.

It is hoped that Project X will test the limits of particles physics’ rule book – the so-called ‘standard model’ – and perhaps find answers to the puzzles that the current theory cannot answer.

Although the standard model is hugely successful, it has some embarassing holes it. For example, it fails to explain how that most familiar of fundamental forces, gravity, fits into the subatomic world. Which, when you consider its effect on the big world we inhabit, is quite important.

Project X ambitions

Why do particles have mass?
Find particles beyond the standard model
What is dark matter...and dark energy?
Do the forces of nature come together at high energies?
Why is universe made of matter (and not antimatter?
How did the universe form?

Project X would send a beam of protons down a linear accelerator, propel them to either 3 or 8 billion electron volts (GeV), and smash them into a target, creating a gusher of fundamental particles. It will generate the most intense beam of high-energy neutrinos ever created.
These distinctive particle types would be sorted and shipped to different detectors for experiments aimed at answering fundamental questions: How did matter come to dominate the universe? Do electrons and other leptons change into each other in the same way the three types of neutrinos do
?