Collider Crossroads

ll the world is built out of 17 known elementary particles. Carlo Rubbia led the team that discovered two of them. In 1984, Rubbia shared the Nobel Prize in Physics with Simon van der Meer for their “decisive contributions” to the experiment that, the year before, had turned up the W and Z bosons. These particles convey one of the four fundamental forces, called the weak force, which causes radioactive decay.

Rubbia ran the experiment, called Underground Area 1 (or UA1), a bold and ambitious project at CERN laboratory near Geneva that sought traces of W and Z bosons in the chaos of high-energy particle collisions. Hundreds of billions of protons and antiprotons were accelerated close to the speed of light and then smashed together. At the time, antiprotons—which have a habit of rapidly destroying themselves when they come into contact with matter—had never been produced in abundance. Some of Rubbia’s peers favored alternative collider and detector designs, believing that antimatter was too volatile to be controlled in this way.

“We had zillions of different ideas. There was a lot of competition, but you cannot do two things at the same time,” Rubbia said. In the end, UA1 prevailed, and delivered.

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