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Mysteries of the Universe: Cern launches accelerators
The largest research machine in the world: Cern starts the particle accelerator after a three-year break. Photo: Laurent Gillieron/KEYSTONE/dpa
© dpa-infocom GmbH
The countdown is on for physical discoveries that could overturn today’s explanatory model of the universe. At CERN in Geneva, protons are again being sent on a collision course.
After a good three years of maintenance and improvement work, the largest research machine in the world is started up again: the particle accelerator of the European Organization for Nuclear Research (CERN) in Geneva.
This Friday, the first two proton beams are to be chased in opposite directions through the 27-kilometer underground ring. It takes six to eight weeks for the machine to be up to speed. Only then can proton collisions take place again, which should reveal knowledge about the fundamental laws of the universe.
High tension until the last minute
The preparations have been going on around the clock for a few weeks. Tension reigns in the Cern control rooms until the last minute. “It’s like a rocket launch,” says German CERN research director Joachim Mnich of the German Press Agency. “It often has to be canceled minutes before the start because a problem arises. But we hope that everything will go smoothly.”
In this case, the proton beam, which was started at the push of a button and circulates through the ring, can be seen on computer screens after a short time. “Before this can happen, the proton beam usually has to be shifted by a millimeter using electronic signals and it sometimes has to be guided through the eyes of a needle, which doesn’t always work right away,” says Mnich.
Emergence of the universe simulated
The particle accelerator is used to simulate the time when the universe came into being around 14 billion years ago. Researchers observe the decay processes during the collisions and gain insights into the smallest components of matter, the elementary particles. Among other things, the Higgs boson, which was theoretically described 40 years earlier, was detected for the first time at CERN in 2012. It contributes to the fact that elementary particles have a mass.
During the shutdown, the performance of the accelerator and the connected detectors has been significantly increased. This means that even more collisions are possible, around 1,000,000,000,000,000 a year, a quadrillion, as Mnich says. However, only one of perhaps 100,000 collisions reveals processes that are worth closer analysis. Although the data is stored within milliseconds, the evaluation often takes years.
Unknown forces of nature and newly discovered particles?
This was the case at the US research center for particle physics Fermilab, which came up with a sensation at the beginning of April: physicists had recalculated the W boson from data more than ten years old, which transmits one of the four basic forces that determine the behavior of matter in the universe . The researchers determined with high precision that it is heavier than the Standard Model of particle physics predicts. This model describes twelve matter particles and their interaction.
The W boson was discovered at CERN in 1983. There, Mnich hopes, the results of the Americans can be confirmed or disproved in the next few years. “If the result is correct, this could be an indication of an unknown force in nature, or an indication of additional particles that we have not yet known about,” says Mnich.
An anomaly that deviates from the Standard Model of particle physics was also discovered at CERN last year in a completely different context. Beauty quarks did not decay into muons and electrons in equal parts, as expected. With much larger amounts of data, physicists are now hoping for new insights that could raise even more questions about the validity of the Standard Model.