It’s the most fundamental question possible: Why is there something, instead of nothing? When the universe was created, theory says that matter and antimatter should have been created in equal measure, and we know that when these two types of particles meet they react by annihilating one another. By all accounts, the universe should never have been able to get started, should have wiped itself out immediately. So, what happened? Was there less antimatter created than we predicted, or did we somehow avoid the annihilation process? Why does the universe contain matter at all? One way of investigating these questions is to study neutrinos, and for several years the “EUROnu” project has been trying to decide the best way of doing so. This month, the commission presented its findings at CERN: they want to build the Neutrino Factory.

This refreshingly acronym-free device creates beams of neutrinos by smashing protons into a solid target, creating muons which reliably decay into neutrinos. The beam would be fired roughly downwards, traveling 2,000 kilometers or more to the receiving end. The emitter will probably be at CERN, in Switzerland, though the receiver has been proposed to go anywhere from Japan to Italy to the UK. Regardless, upon arrival the beam of neutrinos will be analyzed for its content: what proportions of the three types of neutrinos are found, and how they compare to the proportions in the beam when it left the emitter. Such investigations into the interconversion of neutrinos and anti-neutrinos could shed light on the nature of antimatter (among other things).

The EUROnu group considered three proposals for performing tests similar to this, and determined that the Neutrino Factory would produce the most accurate results. However, it is also the most expensive option by far. Their cost estimates put the facility between 6.1 and 8.1 billion dollars. The other two options, known as the Super Beam and Beta Beam, might cost about a quarter or a third as much, respectively.

One major factor that influenced their decision was a staged approach to constructing the Neutrino Factory, each step of which could be useful in its own right. The vSTORM project would function as a prototype for the Neutrino Factory and result in a storage ring full of circulating muon particles. This ring could itself be used for several high-level experiments, including the search for sterile neutrinos, a theoretical type of particle that ignores all properties of the standard model of physics, save gravity.

They do hedge their bets, claiming that if certain other projects are brought to fruition independently, their recommendation might change. For instance, if the MEMPHYS detector were to be built elsewhere, probably for investigation of proton lifetimes, they could justify creating the Super Beam as a minor addition. This would make the Super Beam option just another step on the way to the Neutrino Factory.

To put the proposal into context, the Large Hadron Collider, an infamously long and expensive project in its own right, cost less than the commission’s upper-bound estimate for the Neutrino Factory. Since the LHC only stretches into a paltry two countries, this Europe-spanning neutrino beam could be a truly international project — not that the intervening countries could do much to stop the beam, should they want to.

CERN recently updated its stance toward fundamental research into particle physics, expressing optimism about another proposed neutrino gun, this one to fire the particles along the 1,300-kilometer span between Fermilab in Illinois (aboveimage) and a mine in South Dakota. There’s no guarantee that the Neutrino Factory will actually be built, or indeed if any of the three options will see the light of day, but here we have a reasoned argument in favor of what might be humanity’s next great foray into particle physics.

The LHC has and will continue to investigate the nature of gravity, why matter coalesces to allow us to exist. The Neutrino Factory could investigate why that matter even exists in the first place.

POSTED FROM EXTREME TECH