Antimatter.It’s not just the stuff of science fiction. The physicists working at CERN – officially the European Organization for Nuclear Research – create it almost every day as part of their efforts to find out what the universe is made of and how it works. Headquartered in Geneva, Switzerland, CERN is a consortium of 23 countries and includes scientists and workers from many more.Their research lab is a ring-shaped underground tunnel, 27 kilometers around, that crisscrosses the border between Switzerland and France. In the tunnel lies the Large Hadron Collider, where protons – one of the building blocks of atoms – are made to crash into one another with incredible force, creating, among other elements, antimatter. But just because physicists can make antimatter doesn’t mean they understand everything about it yet. Antimatter is as old as the universe, part of its original creation, in an event often referred to as the “Big Bang.” Ludivine Ceard, physicist with the CMS Collaboration, gestures at the Compace Muon Solinoid – one of the experiments at CERN, in Geneva, looking for the tiniest particles of matter. (Courtesy Robert Gumm.)Ludivine Ceard, a physicist with CERN, discussed one of the theories behind the research.“We have this theory that says that right after the Big Bang, there was creation in equal amount between matter and antimatter,” she said.“In principle, if the difference between the two is only the charge, they should have just recombined and left nothing but radiation; however, we are here. I’m talking with you right now. So it means that at some point, matter took over the antimatter, and this must be because there are some differences between matter and antimatter that we don’t know about,” Ceard said.Searching for those differences is one of the tasks for the people at the Compact Muon Solenoid, or CMS, one of four main experiment sites around the Large Hadron Collider at CERN. A muon is one of the so-called elementary particles, one with no smaller components. It is similar to an electron, but heavier. And while it is very, very tiny, the machine built to study it is large. A CMS staff member walking near the structure when VOA visited was dwarfed by the apparatus designed to study the muon.A cutaway illustration of the tube carrying the proton beams around the Large Hadron collider. The tube has been removed for maintenance. (Courtesy Robert Gumm)To create muons and antimatter, packets of protons race around a circular track in the LHC in two beams, one traveling clockwise and one counterclockwise near the speed of light. When the physicists are ready, the beams are focused and made to collide at just the right spot. Rende Steerenberg heads the group in charge of seeing those collisions happen. “On either end of the experiments we will switch on focusing magnets so that the beam squeezes into a small dimension and therefore the probability of collision increases,” he said.Even so, with 100 billion protons in a packet moving in one direction, and another 100 billion protons moving the other way, only 50 protons are likely to collide.Right now, the probability of a collision is zero – because the collider and the experiments around it are in the midst of a two-year shutdown for maintenance and upgrades – which happens every three years. You might think that would leave the scientists feeling frustrated, but you would be wrong. Patricia McBride, physicist with Fermilab, and deputy spokesperson of the CMS Collaboration in Geneva. (Courtesy Robert Gumm)The deputy spokesperson of the CMS Collaboration, Patricia McBride from Fermilab in the U.S., says what we might think of as down time is anything but.“I would say that for us it’s an opportunity. It’s also one of the busiest times for us because not only are we looking at the data that we’ve collected from the LHC from the last two rounds, but we’re looking at ways of making the detector better, repairing things, putting in new detectors, and preparing for the future runs which the experiment will be running until we hope till 2035,” she said.The collider was built in 10 years. Shortly after going into operation, it immediately made its predecessor, the Tevatron, a circular collider at the United States’ Fermilab in Illinois, obsolete. The Tevatron shut down in September 2011, not long after the LHC created its first particle collisions. But the researchers at Fermilab weren’t devastated by their eclipse. In fact, they helped build the new collider, and when it opened, they presented the new team with a baton – like those used in relay races – to symbolize the continuation of their research efforts. The CMS collaboration includes some 4,000 Scientists from more than 50 countries from across Europe, India, China, South Korea, Egypt, other parts of the Middle East and Russia.The discoveries and developments made at CERN are already helping to transform fields as diverse as nuclear waste disposal, medical testing, detection of art forgeries and efforts to disrupt financial markets. Technologies developed for CERN are also finding uses in optimizing farm irrigation, in creating sensors that detect water pollution, and in speeding up machine learning, to create better software for self-driving vehicles. And while the scientists love when the experiments confirm their predictions, they also love it when things don’t turn out as expected – because that might be saying something very fundamental about antimatter – and how the universe is put together.
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