LHC Lunch

Meet Peter Jacobs

At the center of the world

The seats Peter Jacobs and I found are in a relatively quiet corner of the CERN cafeteria, yet assorted colleagues of his still interrupted us several times as they stopped to say hello. At CERN, he said, “You can use the cafeteria as your office. Sit here with a cup of coffee, and eventually the whole world comes by.” This was not always the case.

Jacobs began working for California’s Lawrence Berkeley National Laboratory on heavy ion physics in 1988. He’s been travelling between California and CERN to do his research ever since.

“You always felt like you were at the center of the world, in terms of particle and nuclear physics,” Jacobs said of the era. But whereas LEP felt like a European-centric project with a few contributions from the United States and China, the LHC seemed to draw in the whole world.

The change came in the early 2000s during the accelerator’s construction, Jacobs said. “Once the LHC was approaching reality, there were many other countries with a notable presence.” TV crews started to appear; the number of people at the lab grew. “The whole level kind of rose to where you felt this was something of international prominence,” he said. “It just became a world laboratory.”

Jacobs and his anthropologist wife frequently discuss the sociological aspects of large scientific collaborations, including those at CERN. “I find the juxtaposition of rigorous and beautiful science with the complexity of human interactions fascinating,” he said. Although the content failed to impress him, a study of the sociology of physics collaborations in prior eras that Jacobs read left him intrigued by the subject. With such things as power, prestige and money at stake, physics collaborations can seem like microcosms of larger human systems.

CERN is a bit like Renaissance Italy, he said, attributing the analogy to a colleague. Everyone brings a certain number of resources to the laboratory, but no one has enough to conquer the whole place alone. Instead they must negotiate and cooperate. The system is not a democracy, though the discussions may be democratic, he said. In practice, science involves picking research avenues from a marketplace of proposals. “Hopefully the best ideas are the ones that gain currency, and off we go.”

As far as his own work, he said that heavy ion physics “is different than the main thrust of the LHC, [which is] the energy frontier.” The laboratory’s heavy ion program runs for only a few weeks at the end of every year, when the accelerator switches its projectiles from protons to lead nuclei. Unlike the usual collisions, which give scientists clues about new particles and symmetries, lead collisions are researchers’ way of studying matter at big bang-like conditions of extreme temperature and density. To do this, they want to smash the most massive nuclei in nature. “It would be nice to collide neutron stars,” Jacobs said.  Instead, lead nuclei will have to suffice.

Heavy stuff might describe not only Jacobs’ specific area of research but also what he likes best about nuclear and particle physics overall: being able to “both ask and answer the big questions.” At the LHC, “We’re trying to understand matter, and it’s not clear what should happen at these new energies,” he said. “That’s why I’m here.”