In September, a group of particle physicists working in Italy made a dramatic announcement. They announced results — and not just one or two outlier results but a metric truckload of results — that suggested that beams of particles known as neutrinos created at CERN in Switzerland were violating the laws of physics established by Albert Einstein by travelling to the OPERA neutrino detector at a speed that was faster than the speed of light.
And the press went crazy.
But what are neutrinos? And what does the OPERA result mean for the Universe? Well, you’re going to have to listen to the whole hour to find out.
So where to begin?
In 1930, Wolfgang Pauli — along with a bunch of other physicists of the time — noticed that the products of certain types of nuclear decays didn’t add up. Specifically, the energy and the momentum before the reaction were greater than the momentum and energy after the reaction. So Pauli postulated the existence of an extra particle — a particle with no electric charge — that he called the neutron.
A few years later. James Chadwick discovered another particle that he also called the neutron. But this couldn’t have been the particle that Pauli had postulated — it was TOO BIG! So Enrico Fermi suggested that Pauli’s particle be called something else. He called it a neutrino — literally ‘little neutral one’!
But he still hadn’t any evidence for it. So when he sent a theoretical paper unifying the electron, the proton, the neutron and the neutrino to Nature, it was declined as “too remote from reality” to be likely.
So how do we know that neutrinos exist? Why are they so controversial? Is it responsible for the dark matter in the Universe? And do they violate the laws of physics?
We ask neutrino guru, Dr Ryan Nichol.