In 2012, after decades of searching, physicists announce the discovery of the “god particle” Higgs boson – but there are still many unanswered questions. The largest and most powerful particle accelerator in the world, the LHC at CERN in Geneva, is supposed to help with the answer. He’s running at full speed now.
Ten years after the discovery of the Higgs particle, new experiments are starting in the world’s largest and most powerful particle accelerator, the LHC, near Geneva. The scientists at the European Organization for Nuclear Research (CERN) are hoping for new discoveries. In this way, they want to further decode the mysteries of matter.
After a three-year hiatus for modernization, the Large Hadron Collider (LHC) restarted in April to prepare for its third run. As of this Tuesday, it will work around the clock for almost four years with a record energy of 13.6 tera-electron volts (TeV), as the CERN researchers announced.
Two proton beams are accelerated to almost the speed of light and circle in opposite directions in the 27-kilometer ring tunnel 100 meters underground. The collisions of the protons are being recorded and analyzed by thousands of scientists in a series of experiments.
“We are aiming for a rate of 1.6 billion proton-proton collisions per second,” says CERN researcher Mike Lamont. The more violent these collisions are, the easier it is to “break up” the particles in order to identify their components and interactions. To increase the collision rate, the proton beams would be narrowed to less than 10 microns, Lamont explains. A human hair is about 70 microns thick.
Compared to the first run of the particle accelerator, there will now be 20 times more collisions. “This is a significant increase and paves the way for new discoveries,” says Lamont.
The higher energy will allow scientists to further study the Higgs boson, the detection of which CERN announced on July 4, 2012. It was the last missing building block in the Standard Model of particle physics.
Since 1964, physicists have been using the so-called Higgs mechanism to explain how the particles – i.e. the basic building blocks of matter – get their mass. Several recent discoveries have raised questions about the Standard Model, which will now be explored in detail in the upgraded particle accelerator.
There is still a lot to learn about the boson, says German physicist Joachim Mnich, head of research at CERN. “Is it an elementary particle or a composite one? Is it the only Higgs particle or are there others?” Mnich names two of the open questions. Experiments so far have not only determined the mass of the Higgs boson, but also discovered more than 60 composite particles predicted by the Standard Model, such as the tetraquark.
“But particles are just the manifestation of a phenomenon,” says Gian Giudice, head of CERN’s Theoretical Physics department. However, the goal of particle physics is to “understand the fundamental principles of nature”. For example the nature of the hypothetical Dark Matter or the no less mysterious Dark Energy. Nine experiments will use the accelerator’s particle production and examine, for example, the primordial plasma that prevailed in the first ten microseconds after the Big Bang.
The particle accelerator – the largest machine in the world – is now scheduled to run for four years. But the CERN researchers have been looking further into the future for a long time and are planning a new accelerator: the ring tunnel of the Future Circular Collider (FCC) should be 100 kilometers long.
(This article was first published on Tuesday, July 05, 2022.)
