Proton beams are circulating along the ring again 27 kilometers from the collider.
Ten years after its discovery of the Higgs boson, the Large Hadron Collider (LHC) of the European Center for Nuclear Research (CERN) will restart on Tuesday at record collision energy. The goal? Drill a little deeper into the secrets of matter.
The LHC is the largest and most powerful particle accelerator in the world. It was put back into operation in April after a three-year technical shutdown for maintenance work and to improve its particle detection capabilities.
It will operate at its full collision power of 13.6 billion billion electron volts (TeV) for four years, CERN officials announced in a press briefing last week.
Its two beams of protons (the particles of the nucleus of the atom), accelerated to a speed close to that of light, will circulate in opposite directions in the 27 km ring, buried 100 meters underground at the Franco-Swiss border.
The detectors of several experiments (in particular ATLAS, CMS, ALICE and LHCb) will then record the collisions of protons, which produce ephemeral particles explaining the operation of matter.
We are aiming for a rate of 1.6 billion proton-proton collisions per second for the ATLAS and CMS experiments, said Mike Lamont, director of accelerators and technology at CERN.
The more violent these collisions, the more they make it possible to break up the particles to identify their components and their interactions.
The proton beams will be concentrated to reach at the points of interaction a microscopic size, 10 microns, to increase the proton collision rate, explained Mike Lamont.
The world temple of the infinitely small, built in 2008, allowed the discovery of the Higgs boson, announced exactly ten years ago by Fabiola Gianotti, then coordinator of the CMS experiment and today Director General of CERN.
The Higgs boson is linked to some of the most profound questions in fundamental physics, whether it be structure and the shape of the Universe, such as how other particles organize themselves, according to the researcher.
His discovery revolutionized physics, confirming the prediction of researchers who had made it a centerpiece of the Standard Model of particle physics nearly 50 years earlier. The Higgs boson is the manifestation of a field, that is, a space, which gives mass to elementary particles forming matter.
The researchers were able to flush it out by analyzing about 1.2 billion billion proton collisions with each other. The third run of the LHC which opens on Tuesday will multiply this figure by twenty. This is a significant increase that 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 one, namely an assembly of several still unknown particles, asks Joachim Mnich, Director of Research and Computing at CERN. Better, is it the only existing Higgs particle or are there others?
Past experiments have determined the mass of the Higgs boson , and also to discover more than 60 composite particles predicted by the Standard Model, such as the tetraquark.
But as Gian Giudice, head of the theoretical physics department at CERN, reminds us, particles are only the manifestation of a phenomenon, whereas the objective of particle physics is to understand the fundamental principles of nature. Like the nature of the hypothetical dark matter or the no less mysterious dark energy.
Nine experiments will thus take advantage of the production of particles from the accelerator. Like ALICE, which studies the primordial plasma of matter that existed in the first ten microseconds after the big bang. Or LHCf, which simulates cosmic rays.
The next stage of the Large Collider will come after the third break, in 2029, with its transition to high luminosity, which will multiply by ten the number of detectable events.
Beyond that, CERN researchers are looking towards the Future Circular Collider (FCC) project, a 100 km ring whose #x27;feasibility study is expected at the end of 2025. It will be the ultimate machine to study the Higgs boson, which is a very powerful tool for understanding fundamental physics, concluded Fabiola Gianotti.