What is super asymmetry

Nobel Prize in Physics: Theory of Asymmetry

This year, three Japanese, one of whom is a US citizen, are sharing the award. It's about symmetry and how and when it is broken.

After a fairly practice-oriented Nobel Prize in Physics in 2008 (for the discovery of a magnetic effect that is important for computer hard drives), the theory strikes again this year, more purely than it has been since 2004: At that time, three Americans were awarded for work on the theory of strong nuclear power, this year they are there three Japanese. They too have been particularly concerned with the strong nuclear force - that is one of the four fundamental interactions: the force that holds the quarks together in the particles (protons, neutrons) that make up the atomic nucleus - but their concepts are still of fundamental importance .

It's about symmetry and how and when it is broken. Symmetry is very important in theoretical physics, many physicists rave: It is the most important thing (see article on the right below).


Solid state physics concept

The concept of spontaneous symmetry breaking actually comes from solid state physics - symmetry is obviously important in crystals. Mainly from the theory of superconductivity: a phase transition at a certain temperature - such as melting or the transition from non-superconducting to superconducting - is accompanied by a symmetry break.

Yoichiro Nambu was the first to apply this concept to particle physics, where it is "extremely helpful" to this day, as the Nobel Prize Committee says. That was in 1960, four years before Murray Gell-Mann founded the Quark model. At that time, the theory of strong nuclear force was far from being formulated: Nambu's ideas about the quantum field theories on which it was supposed to be based were trend-setting; the electric charge. Nambus formalism was also exemplary for the field theory, which should bring us the most sought-after particle in physics: the Higgs boson, whose field should give many, if not all, particles their rest mass.


There must be six quarks!

The other two new Nobel Prize winners, Makoto Kobayashi and Toshihide Maskawa, applied the concept of symmetry breaking primarily to the coupling of strong and weak nuclear forces - and to the question: why and in which processes is CP symmetry (the combination of charge and and mirror symmetry) violated? They were able to explain the symmetry breaking - but only on the assumption that there are not only the three quarks that were known at the beginning of the 70s (Up, Down, Strange), but three generations of two quarks each. The three quarks they had just predicted (Charm, Bottom, Top) were all later confirmed in experiments, two of them in particle accelerators.

Another prediction of the two laureates was later confirmed experimentally: that a certain (non-elemental, but rather consisting of two quarks) particle, the B meson, decays differently than its antiparticle. Unfortunately, this break in symmetry is not enough to explain why antimatter and matter do not appear to be in completely equal amounts in the universe. (And with it, why not all particle pairs have dissolved into energy.) And so the Nobel Prize Committee cannot avoid hoping out loud that the results of the great renown and trembling project in physics, the LHC in Geneva, will show the way for theory : "Perhaps the LHC will unravel some of the secrets we are working on."


("Die Presse", print edition, October 8th, 2008)