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).