Article by Marcus du Sautoy

Two years ago, a mathematician and physicist whom I’ve known for more than 20 years arranged to meet me in a bar in New York. What he was about to show me, he explained, were ideas that he’d been working on for the past two decades. As he took me through the equations he had been formulating I began to see emerging before my eyes potential answers for many of the major problems in physics. It was an extremely exciting, daring proposal, but also mathematically so natural that one could not but feel that it smelled right.

He has spent the past two years taking me through the ins and outs of his theory and that initial feeling that I was looking at “the answer” has not waned. On Thursday in Oxford he will begin to outline his ideas to the rest of the mathematics and physics community. If he is right, his name will be an easy one to remember: Eric Weinstein.

One of the things that particularly appeals to me about the theory is that symmetry, my own field of research, is a key ingredient. Of course the idea that the fundamental particles of nature are intimately connected to questions of symmetry is not new. But despite the great successes of the Standard Model there remain some very strange questions that have intrigued physicists for some years.

The particles described by the Standard Model – the stuff of nature that is revealed in accelerators such as the Large Hadron Collider – fall into three “generations”. In the first generation we see the electron, the electron neutrino, six quarks and their anti-particles, making 16 in total. But then rather bizarrely in the second generation we have another version of these particles which look exactly the same but are heavier than the first generation.

The heavier version of the electron is called the muon. The physicist Isadore Rabi famously quipped on hearing about the muon: “who ordered that?” It didn’t seem to make sense that you should have a heavier version of all the particles in the first generation. What was the logic in that? To compound things, there is a third generation heavier again than the second whose electron partner is called the tau particle.One of the challenges facing fundamental physics has been to provide a natural explanation for these three generations. Weinstein’s theory does this by revealing the presence of a new geometric structure involving a much larger symmetry at work, inside which the symmetry of the Standard Model sits. What is so compelling about the geometry involving this larger symmetry group is that it explains why you get two copies of something with 16 particles but also that the third generation is something of an imposter. At high energies it will actually behave differently to the other two.

Edited from Marcus du Sautoy’s Guardian article. Read the rest here Eric Weinstein may have found the answer to physics’ biggest problems