October 7, 2008

scientists comment on the 2008 Nobel Prize for Physics

This year’s physics prize was awarded to Yoichiro Nambu, Makoto Kobayashi and Toshihide Maskawa for their work on broken symmetry in subatomic physics.

Prof Sir Chris Llewellyn Smith FRS, Director of the United Kingdom Atomic Energy Authority (UKAEA) and Director General of CERN 1994-98, said:

“The award of a Nobel Prize to Yoichiro Nambu for his work on hidden symmetries of nature is long overdue. Hidden symmetries allow simple, economical laws to give rise to very diverse, apparently unrelated, phenomena. They play a key role in the unification of different forces in the successful ‘Standard Model’ of particle physics. Makoto Kobayashi and Toshihide Maskawa are also worthy winners for their discovery that an additional ‘family’ of quarks, which was subsequently discovered, is needed to allow certain symmetries of nature to be broken.”

Prof Will Stewart, Fellow of the Royal Academy of Engineering, said:

“This is indeed great stuff and an important advance in fundamental physics – but still, Nobel’s original specification said ‘to those who, during the preceding year, shall have conferred the greatest benefit on mankind’ – which is generally regarded as meaning the prize is for applied rather than basic Physics. Considering the major problems facing mankind right now a more applied, but still intellectually outstanding, choice (as is made for medicine) next year might be in order! There are plenty of possible choices.”

Prof David Wark, Particle Physicist at the STFC Rutherford Appleton Laboratory, said:

“I was the chair of the European Physical Society High Energy Particle Physics Division last year when we awarded the EPS HEPP Prize to Kobayashi and Maskawa for their work on quark mixing. This continues our record of being able to predict the winners of the Nobel Prize (recently we awarded the prize to Gross, Wilczek, and Politzer the year before they won a Nobel, and there are many other examples). The citation for our prize read: ‘For the proposal of a successful mechanism for CP violation in the Standard Model, predicting the existence of a third family of quarks.’ I think this sums up the remarkable consequences of their model. With one extremely simple hypothesis they produced a model which provides a simple mechanism for the puzzling observation that the laws of physics are observed to be very slightly different for matter and anti-matter and predicted the existence of a third generation of quarks (before the discovery of the charm quark, which was the last of the second generation to be discovered).”

Dr Malcolm Fairbairn, Lecturer in the Department of Physics, Kings College London, said:

“The winners of this year’s nobel prizes were three of the leading figures in particle physics theory in the 20th century.

“Nambu’s work on spontaneously broken symmetries in particle physics had an effect in many areas of particle physics, for example, it is a crucial part of the theoretical journey which lead to the prediction of the Higgs boson in the standard model of particle physics, now being searched for at the Large Hadron Collider (LHC) in Geneva.

“Quarks are objects which experience electromagnetism, the strong nuclear force and the weak nuclear force. Kobayashi and Maskawa extended previous work by Cabibbo in studying the way that different quarks experience the weak nuclear force. The fact that different quarks experience the weak force differently is an example of a broken symmetry in nature, and Kobayashi and Maskawa were able to study these broken symmetries to predict the existence of a third generation of quarks which were subsequently discovered. Now physicists are trying to pin down all the details of these broken symmetries which are encoded in an object called the Cabibbo-Kobayashi-Maskawa matrix. This matrix also contains information which might shed light on why there is more matter than anti-matter in the universe, in fact an experiment at the LHC called LHCb has been specifically designed to understand the details of this matrix.

“The fact that pioneering work of all three of these physicists is so close even today to the coal face of scientific knowledge is a testament to their skill and ingenuity.”

Dr Pete Edwards, Science and Society Officer, in the Ogden Centre for Fundamental Physics,at Durham University, said:

“For an everyday example of spontaneous symmetry braking consider a pencil balanced on its point.

“The pencil lives in a completely symmetrical world in which all directions are equal.

“Invariably the pencil will fall over and this original symmetry is lost. Only one direction is now important for the pencil which is now more stable and cannot fall any further. This is spontaneous symmetry braking.

“We believe our universe is filled with the Higgs field that, like the pencil standing on its end was not stable in the early universe. The spontaneous broken symmetry of this field explains why we have mass.

“The Large Hadron Collider will look for evidence of the Higgs field.”