Clash of the protons

Heed the old saying "Don't judge a book by its cover". Particle physicists will be dismayed to see the cover of Gordon Fraser's book liken their science to a campaign of war, with physicists on both sides of the Atlantic battling for supremacy in the quest to find and understand the smallest particles of matter. By contrast, a central theme of The Quark Machines is that particle physics has long recognised the value of collaboration on an international scale when it comes to cracking scientific problems.

Fraser charts the history of particle physics from a different angle, concentrating on the enormous effort that has gone into developing present-day particle accelerators - some of the largest scientific instruments known. These huge atom-smashers accelerate subatomic particles close to the speed of light through a myriad underground magnetic racetracks and crash them together. Like a high-energy microscope, the particles can probe deep inside the structure of matter or be used to create new kinds of particles that are not seen in everyday life, but were created shortly after the Big Bang. The story is compelling as it tells of the political decisions and personalities that have shaped the science, as well as the science itself. Packed full of lively anecdotes and imaginative analogies, Fraser makes the science clear and readily accessible.

The second world war had an unquestionable and lasting impact on nuclear physics. Hitler's actions in 1933 prompted a flood of European physics talent to emigrate to the United States and helped to catapult the country to sub-nuclear stardom in the space of a few years. It sparked one of the greatest single scientific undertakings - to develop the atomic bomb. The skills of the immigrants, coupled with the financial might of the US, transformed a bench-top science experiment into the world's most strategic weapon in just two years. The close collaboration among researchers, a well-defined aim and the concentration of resources in a single major research centre proved invaluable. By bringing the war to such a decisive end, American physicists were regarded as heroes and were rewarded with power and funding that kept them at the forefront of research for decades to come. "To do physics was patriotic," states Fraser.

Before the war, Ernest Lawrence at the Berkeley laboratory in California had struggled for money to develop a pioneering technique to accelerate charged particles to high energies. During the war, particle accelerators went on to find widespread applications in industry and medicine. With lavish post-war funds, particle accelerators sprang up across the US reaching higher energies and larger dimensions. The new machines delivered intense, controlled beams of high-energy particles that made studying sub-nuclear interactions a more quantitative science. Meanwhile, their European counterparts, who had previously led the field conducting experiments on mountain tops with cosmic rays, soon found themselves left behind. After the war, they put aside their national differences and lobbied Unesco to help set up a European centre dedicated to particle physics research. The laboratory would promote international collaboration to achieve goals larger than those that could be reached by a single country. After tireless campaigning, the European Centre for Particle Physics (Cern) was born in 1952. Its ambition to build the world's largest particle accelerator, despite little expertise of the new accelerator techniques within Europe, was a bold one.

Collaboration and assistance among international groups in particle physics is always available, with new breakthroughs applauded whoever makes them. The Europeans visited the Brookhaven laboratory near New York to learn how to build a scaled-up version of the American proton synchrotron. During the visit a simple yet revolutionary idea to give protons more energy for the same price-tag was spawned.

Cern gambled on the new and untested idea, and in 1959 its proton synchrotron accelerated protons to energies far surpassing machines elsewhere and beating the latest Brookhaven machine by several months. The joy was shortlived, as Fraser recounts. Although Cern had invested much in building the machine, little attention had been paid to the experiments needed to study the particle collisions. With the far-sightedness, ingenuity and daring that experience and high-level funding can bring, the Americans beat their European counterparts to important discoveries time and again.

Fraser tells how each Cern director made his mark on the laboratory and how it took bold and daring decisions to give Cern its first Nobel prize for the discovery of the heavy W and Z particles in 1983. These two particles carry the weak force responsible for radioactive beta-decay and were the most important pieces in the theoretical jigsaw of the time. Their discovery supported the theory on which our understanding of the basic building blocks of matter, and the forces acting between them, is built.

But the jigsaw still has some big pieces missing. How do all these basic blocks get mass in the first place? The answer is thought to lie with a mass-giving particle called the Higgs boson that is still to be discovered.Yet even if the Higgs boson is discovered, it will raise as many questions as it answers, as though the jigsaw has suddenly become larger. A new accelerator called the Large Hadron Collider, which will provide the highest energy and most intense beams of protons to date, is being built at Cern to attack the problem.

Fraser outlines the political challenges that Cern faces in raising the finances to undertake such a massive project for the beginning of the 21st century. He recounts decisions taken on the other side of the Atlantic that marked the turning point in the US domination of particle physics in 1993. With spiralling costs, allegations of mismanagement and a changing political climate, Bill Clinton halted construction of a vast 87km atom-smasher in Texas to complement the European machine. The flagship of American physics in the 21st century had been sunk.

The Quark Machines is more than just a book on particle physics; it charts the ambitions and enthusiasm of particle physicists in breaking down national barriers and working collectively to further their science. Fraser's book will appeal to anyone interested in science.

Valerie Noyes is a research fellow, Particle and Nuclear Physics Laboratory, University of Oxford.