AFP, published on Monday, July 04, 2022 at 6 p.m.
Ten years after its discovery in the Higgs boson, CERN’s LHC, the world’s largest and most powerful particle accelerator, will start again on Tuesday at record collision speed. The goal? Drill a little into the material secrets.
The Large Hadron Collider (LHC) was restarted in April, after a technical shutdown for three years, for continued work and to improve particle production and analysis.
It will operate at full power at its 13.6 trillion electron volts (TeV) collision for four years, officials at the European Organization for Nuclear Research (CERN) announced at a press briefing last week. .
The two beams of its protons – the particles in the nucleus of the atom -, accelerated at speeds close to light, revolve in opposite directions in the 27 km ring, which is buried 100 meters underground on the Franco border. -Swiss.
The detectors in many experiments (in particular ATLAS, CMS, ALICE and LHCb), immediately record collisions of protons, producing ephemeral particles that explain the motion of matter.
– 1.6 billion collisions per second –
“We expect a rate of 1.6 billion proton-proton collisions per second for ATLAS and CMS experiments,” Mike Lamont, director of accelerators and technology at CERN, said Thursday.
The more violent these collisions are, the more they make it possible to “break down” particles to identify their components and their interactions.
The proton beams will concentrate to reach at points of interaction a microscopic size, “10 microns, to increase the collision rate” of the protons, Mike Lamont explains.
The world temple of infinity 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 at CERN.
“The Higgs boson is involved in 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, confirming the prediction of the researchers who made it, almost 50 years ago, a centerpiece of the Standard Model of particle physics (SM). The Higgs boson is the representation of a field, which is a space, that gives mass to the elementary particles that form matter.
– More secrets to be given –
The researchers were able to flush it out thanks to analyzing about 1.2 billion collisions of protons between them. The LHC’s third run that opens on Tuesday will double this number by twenty. “This is a significant increase that opens the way to new discoveries”, said Mike Lamont.
Because the Higgs boson doesn’t reveal all its secrets. Began to characterize it. “Is it a basic particle or a composite”, which is an assembly of many particles that is not yet known, asks Joachim Mnich, Director of Research and Calculation at CERN. Better yet, “is this the existing Higgs particle or is there something else?”
Previous experiments have made it possible to determine the mass of the Higgs boson, as well as to discover more than 60 composite particles predicted by the Standard Model, such as the tetraquark.
But as Gian Giudice, head of CERN’s theoretical physics department, reminds us, “particles are only a reflection of an event”, while “the goal of particle physics is to understand the basic principles of nature”. Like the nature of hypothetical dark matter or less mysterious dark energy.
Nine experiments will thus take advantage of making particles from the accelerator. Like ALICE, which studies the primordial plasma of matter that prevailed in the first ten microseconds after the Big Bang. Or LHCf, which mimics cosmic rays.
The next phase of the big collider will come after the third stop, in 2029, with its transition to “high light”, which will increase by ten the number of visible events.
What’s more, CERN researchers are looking at the upcoming Circular Collider (FCC) project, a 100 km ring whose feasibility study is expected by the end of 2025. “This is the final engine for the Higgs boson study, which is a very powerful tool for understanding fundamental physics, ”concluded Fabiola Gianotti.