In 2008, outside Geneva, Switzerland, physicists turned on the Large Hadron Collider (LHC), the world’s largest particle accelerator and most expensive science experiment ever devised. For many, the cost and wait were worth it. In 2012, the massive machine detected the Higgs Boson, verifying the last major piece of the Standard Model of physics. But researchers know the Standard Model is not complete, since it ignores things like gravity and dark matter. That’s why, on Friday, construction began on a major upgrade to the LHC, reports Ian Sample at The Guardian, and when it is complete in 2026, the more powerful accelerator may just blow the Standard Model to pieces, or at least add a few wrinkles to the theory.
Particle physics is one of the more complicated sciences out there. Most people with a semester of chemistry under their belt understand that atoms are made up of protons, neutrons and electrons. But there’s much more—protons and neutrons are made up of quarks held together by gluons, one of several types of boson. Other elementary particles—those that researchers don’t believe can be divided any further—include six flavors of leptons and the Higgs, known as a scalar boson. Then there are dozens of particles made up of those elementary particles, including hadrons, which are constructed of quarks and gluons, and mesons, made of a quark and anti-quark.
While the science behind the particles is difficult, understanding how scientists find new particles or confirm the existence of theoretical particles is easy—they smash them together and look at the pieces. That’s essentially how the LHC works, reports the BBC—researchers shoot two beams of particles at each other around an almost 17-mile-long ring at nearly the speed of light. Those beams, guided by powerful magnets, are then crossed, causing the particles to smash into one another and breaking into elemental pieces which last for a fraction of a second. Very sensitive detectors pick up those quick flashes of what makes up our universe.
The BBC reports the new upgrade will be called the high-luminosity LHC and it will boost the intensity of those particle beams, increasing the number of collisions by a factor of five or 10. To do that, reports CERN, the agency which runs the LHC, they are adding 130 new powerful magnets that will more precisely control the particle beam, making it more likely that particles will smash into one another. They are also moving some magnets and adding superconducting cables to improve the LHC's efficiency. All that will result in five to ten times more collisions, meaning volumes more data to study, and that has researchers excited. “The high-luminosity LHC is where we will collect most of our data, and in that sense it is the phase of our exploration that lets us find out most about the universe,” Tara Shears of Liverpool University, who works on the collider, tells Sample. “If the LHC so far has given us a candle to illuminate what was previously unseen, the high-luminosity LHC will let us shine a searchlight.”
Ryan F. Mandelbaum at Gizmodo reports that the boost in power is needed. Researchers hoped that after detecting the Higgs Boson in 2012, they would also begin to uncover other particles that could fill out our knowledge of the quantum world. But those finds have been elusive. Researchers have found “whiffs” of new particles which could upset our current models but a more robust collider would help make more solid detections. Mandelbaum also says it could find new particles that help explain dark matter, prove the existence of new dimensions and explore other deep mysteries in physics.
“If the anomalies we see in the LHC at the moment manifest in the next couple of years, which they may well do, what we’ll be looking at with the high luminosity-LHC is the physics underlying those discoveries,” Val Gibson, a professor of physics at Cambridge who works on the collider, tells Sample. “That would turn the standard model on its head. It would be totally groundbreaking.”
Mandelbaum reports that the power boost is also needed to get a better handle on the Higgs. Though it has been detected, researchers have not seen enough of the particle to study it in depth. At the current rate, it would take the LHC a hundred years or more to gather all the data on the Higgs boson. With the upgrade it will take about ten. “The LHC now is a numbers game: We need as much data as possible. To study the Higgs boson after its discovery in 2012 but also because it is pretty clear by now that any other new particles could be rare,” physicist Freya Blekman of Vrije Universiteit Brussel in Belgium tells him. “So we need loads of data.”
Upgrading the machine means it will be offline for two years beginning in 2019, and again between 2024 and 2026. The entire upgrade is expected to cost about $955 million. But if history is any lesson it may take longer and cost more than expected. The LHC has been plagued by cost overruns and technical problems, including a couple of suicidal weasels and a baguette-munching pigeon that each took the machine offline for several weeks.