AFP, published Monday, July 4, 2022 at. 06:00
Ten years after the discovery of the Higgs boson, CERN’s LHC, the largest and most powerful particle accelerator in the world, will restart on Tuesday with record-breaking collision energy. The goal? Lives a little deeper into the secrets of the material.
The Large Hadron Collider (LHC) was restarted in April, after a three-year technical shutdown, for maintenance work and to improve production and particle detection.
It will operate at its full collision power of 13.6 trillion electron volts (TeV) for four years, officials from the European Organization for Nuclear Research (CERN) announced in a press briefing last week.
Its two rays of protons – the particles in the atomic nucleus -, accelerated to a speed close to light, will circulate in opposite directions in the 27 km long ring, buried 100 meters underground at the Franco-Swiss border.
The detectors from several experiments (especially ATLAS, CMS, ALICE and LHCb) will then detect collisions of protons, which produce volatile particles that explain the function of the substance.
– 1.6 billion collisions per second –
“We are aiming for a speed of 1.6 billion proton-proton collisions per second for the ATLAS and CMS experiments,” Mike Lamont, director of accelerators and technology at CERN, said on Thursday.
The more violent these collisions, the more they allow the particles to “crack” to identify their components and their interactions.
The proton beams will be concentrated to reach a microscopic size, “10 microns, at the interaction points, to increase the speed of collisions” of protons, Mike Lamont explained.
The world stamp of the infinitely small, built in 2008, led to the discovery of the Higgs boson, announced exactly ten years ago by Fabiola Gianotti, then coordinator of the CMS experiment and now director general of CERN.
“The Higgs boson is associated with some of the deepest questions in fundamental physics, from the structure and shape of the universe to how other particles organize themselves,” according to the researcher.
His discovery revolutionized physics and confirmed the prediction of scientists who, almost 50 years earlier, had made it a focal point in the standard model of particle physics (SM). The Higgs boson is the manifestation of a field, that is, a space that gives mass to elementary particles that form matter.
– More secrets to hand over –
The scientists were able to flush it out thanks to the analysis of about 1.2 billion billion collisions of protons between them. The third race of the LHC, which opens on Tuesday, will multiply that number by twenty. “This is a significant increase, which paves the way for new discoveries,” notes Mike Lamont.
Because the Higgs boson has not revealed all its secrets. Starting with its nature. “Is it a fundamental particle or a composite”, namely a collection of several particles that are still unknown, asks Joachim Mnich, director of research and calculation at CERN. Better, “is it the only existing Higgs particle, or are there others?”
Previous experiments have made it possible to determine the mass of the Higgs boson, and also to detect more than 60 compound particles predicted by the standard model, such as tetraquark.
But as Gian Giudice, head of the Department of Theoretical Physics at CERN, reminds us, “particles are only the manifestation of a phenomenon”, whereas “the purpose of particle physics is to understand the basic principles of nature”. Like the nature of the hypothetical dark matter or the no less mysterious dark energy.
Nine trials will thus utilize the production of particles from the accelerator. Like ALICE studying the drug’s primordial plasma that prevailed for the first ten microseconds after the Big Bang. Or LHCf, which simulates cosmic rays.
The next phase of the great collider comes after the third pause, in 2029, with its transition to “high brightness”, which will multiply by ten the number of detectable events.
In addition, CERN researchers are looking towards the Future Circular Collider (FCC) project, a 100 km ring whose feasibility study is expected by the end of 2025. “It will be the ultimate machine for studying the Higgs boson, which is a very powerful tool for understanding basic physics,” concluded Fabiola Gianotti.
pcl / juc / cel / fmp / pb