AsianScientist (Jan. 24, 2016) – In one of William Blake’s best loved poems, Auguries of Innocence, he writes about the wonder of “seeing the world in a grain of sand.” Particle physicists like Carlo Rubbia take this several orders of magnitude further, seeing the entire Universe in the tiniest sub-atomic particles known to man.
“Studying sub-atomic particles allows us to repeat the Big Bang story in a way that is very realistic because the Universe was still very uniform microseconds after the Big Bang,” explained Rubbia, winner of the 1984 Nobel Prize in Physics for his role in the discovery of sub-atomic particles known as W and Z bosons.
Rubbia, who was in Singapore earlier this week for the Global Young Scientists Summit 2016 ([email protected] 2016), served as the director-general of the European Organization for Nuclear Research (CERN) from 1989 to 1994. During that time, he launched projects such as the Large Hadron Collider (LHC), which cost US$4.75 billion to build and approximately US$1 billion a year to run.
While some might question the necessity of CERN’s expensive experimental endeavors, Rubbia believes that they are absolutely crucial for addressing fundamental questions of our origins.
“There is no way you can elude these questions which have to do with the essence of man; that’s why so many people have been drawn to working on these problems,” he said.
Seeking the truth in Nature
“As experimentalists, we are natural philosophers, humbly following what Nature decides and tells us,” Rubbia continued. “Our modest approach to understanding Nature needs experimental confirmation that what theory postulates is indeed the truth.”
The theory that the discovery of the W and Z bosons proved was none other than the Standard Model of particle physics, a highly successful theory that explains how the four fundamental forces of Nature are deeply interconnected.
“If you go back a hundred and fifty years, the person teaching electricity and the person teaching magnetism were two different people; electricity and magnetism were considered totally different objects,” Rubbia explained. “But this turned out to be true only under our ‘normal’ conditions.”
Scientists discovered that, at velocities close to the speed of light, electricity and magnetism were actually two sides of the same coin. Later on, Sheldon Glashow, Abdus Salam and Steven Weinberg achieved an even greater theoretical unification, blending electromagnetism with the weak force in the electroweak theory for which they won the 1979 Nobel Prize in Physics.
Despite the recognition of the Nobel Prize, the electroweak theory lacked experimental validation; no one had proven that the W and Z bosons predicted by theory actually could exist. That responsibility fell to Rubbia and his team at CERN, but first, a number of technical challenges needed to be resolved.
The rise of the colliders
To create particles like the W and Z boson for study in the laboratory, researchers make use of energy to generate mass.
“You pay electricity, the accelerator eats power, and the energy generates particles: protons, neutrons, all kinds of things,” Rubbia said.
The first particles made in the 1930s were made with beams accelerated to velocities close to the speed of light, an unbelievable feat for the time. However, the problem with those early accelerators was that they all operated by directing a beam against a fixed target. This arrangement meant that there was less useful energy available for the generation of mass.
The alternative to fixed target accelerators was to aim two beams at each other such that they collide head on. Although this would generate sufficient energy to create the extremely heavy W and Z bosons, it was also extremely technically challenging, akin to shooting two sewing needles at each other from a distance of six miles away from each other and having them collide exactly at the midpoint.
“All these problems require what is called beam compression because the beam produced is diluted and if you want to make two beams collide you have to ‘squash’ them.” Rubbia said.
The breakthrough finally came with the development of beam cooling, a technique developed by Rubbia’s co-laureate Simon van der Meer. By using storage rings, the scientists at CERN were able to increase the intensity of the colliding beams to the point where they were able to successfully demonstrate the production of W and Z bosons in 1982.
“Now that most of the technicalities have been resolved, colliding beams are the main type of accelerator because they can give you a much better use of the system. Over the last 30 years, colliders have permitted a very large number of discoveries, including that of the Higgs boson which was found by the LHC in 2012,” Rubbia added with a touch of pride.
Every individual counts
Large and complex projects such as those undertaken at the CERN highlight that the way science is being done is changing, Rubbia said.
“50 years ago, you had a professor, an assistant, several technicians and a couple of students and that was it. Now you have complicated, multidimensional problems spanning a large number of subjects which each need an expert; you can no longer operate with just a team of ten,” he emphasized.
This new approach to research is not confined to particle physics but also applies to fields like biology, Rubbia maintained, pointing to the example of the thousands of people required to complete the sequencing of the human genome compared to the two people—winners of the 1962 Nobel Prize in Physiology or Medicine James Watson and Francis Crick—recognized for the discovery of the structure of DNA.
But working in large teams does not mean that each individual contribution is devalued.
“In a complicated structure, every person is essential. You cannot say that your job is useless because every person does something fundamentally different. The only problem may be for the Nobel committee because they can only recognize up to three people!” he added with a laugh.
Rubbia noted that teamwork has played a part in the rise of countries like China, Korea and India, where large groups and ambitious projects have helped to galvanize national identify and spurred the proliferation of new ideas.
“For the first time, these developing countries are becoming real competitors; they are all science-oriented, industry-oriented, and making an extremely strong effort to innovate. Furthermore, their populations are mostly young, and young people are more open to change and new ideas,” he said.
“The richness of science is surprise, breakthroughs can happen anywhere. So my advice to young scientists in Asia is to strike out on their own and go where nobody else goes. This is the only way you have the chance to think, invent things and have the time to make your mistakes.”
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