There was a lot of quiet satisfaction in the world of physics this month with the award of the 2013 Nobel Prize in Physics to theoretical physicists Peter Higgs and François Englert. The award follows the discovery in July 2012 of the famous sub-atomic particle known as the Higgs boson at the Large Hadron Collider at Cern, the European centre for particle physics.
It is not every day scientists make a discovery that supports a theory almost 50 years old. In fact, the theory was developed independently by a number of physicists in the 1960s, but Nobel prizes in physics are limited to three individuals at most.
Of course, the experimentalists at the Large Hadron Collider at Cern also deserve recognition, and we can expect the team leaders of Atlas and CMS – the giant particle detectors where the Higgs was independently detected – to be honoured in the near future. In fact, the experiment was the culmination of decades of work by thousands of scientists at Cern and at other particle accelerators worldwide, so the awarding of prizes to individual experimentalists is somewhat symbolic.
The discovery of the Higgs boson marks an important landmark for science. First, it was the last remaining particle of the Standard Model that had not been observed (the Standard Model is the name given to our theory of the sub-atomic world and the fundamental forces that hold it together). Second, the existence of the Higgs particle verifies the existence of an associated Higgs field – theory predicts that other particles acquire their mass by interaction with this field. Finally, the discovery gives strong support to an important part of the Standard Model known as electro-weak theory. This theory predicts that two of the fundamental forces of nature once formed a single interaction in the early universe.
A few years ago, Stephen Hawking said it would be more interesting if the Higgs boson were not found. The remark was not popular with experimentalists who had dedicated their careers to finding it, but it contained an important insight – the Higgs plays such a pivotal role in particle theory that any evidence that it did not exist would have necessitated a radical rethink. Luckily, it was not to be.
With the last piece of the Standard Model in place, more complex theories are now being tested. After the proposal of electro-weak theory, a new generation of theorists began to wonder if all four fundamental forces of nature were once a single unified interaction. This quest was a modern version of Einstein’s famous search for a unified field theory. However, a series of “no-go theorems” soon emerged that seemed to suggest that the quest was once again doomed to failure.
Supersymmetry
In the 1970s, a new theory called supersymmetry was developed that featured a novel framework in which the four fundamental interactions might be unified after all (some aspects of this theory was developed at the Dublin Institute for Advanced Studies). However, the theory also predicted that every known particle should have a sister particle. Since such "supersymmetric" particles had never been observed in experiment, it was postulated that they are extremely heavy particles that decayed early on in the infant universe.
Today, scientists search for particles such as Higgs bosons and supersymmetric particles by recreating the high-energy conditions of the early universe at facilities such as the Large Hadron Collider. Such giant experiments involve large costs and international partnership: 20 European nations plus many associate nations contribute to Cern. Thousands of scientists from universities around the world spend a few months there every year, bringing experimental data back to their institutions to analyse. Graduate students train with world-class scientists.
However, Ireland is not a member of Cern, and Irish scientists, engineers and their students do not get the opportunity to participate in the international experiments at the Large Hadron Collider (one exception is the very successful particle group at UCD). In addition, many lucrative Cern contracts in engineering and computing remain closed to Irish science.
The research at Cern has led to huge technological advances. Perhaps it is time to rethink our participation in such international scientific organisations.
Dr Cormac O'Raifeartaigh lectures in physics at Waterford Institute of Technology and writes the science blog Antimatter. This month, he was elected a fellow of the Royal Astronomical Society