Science. Relaunched at maximum power, CERN’s particle accelerator sparks


It is the largest and most powerful particle accelerator in the world. And its restart after a four-year shutdown proved historic in more ways than one: firstly, barely reconnected, the LHC produced a collision of protons at a staggering level of 13.6 TeV (teraelectronVolt), an absolute record… not obtained without stress:

It’s not about pressing a button. It comes with a certain feeling of tension, nervousness

Rende Steerenberg, Control Room Operations Manager

Many pitfalls, but one record

Among the « traps » that threaten the equipment: an obstruction, shrinkage of materials due to a temperature variation of nearly 300 degrees, potential difficulties with the thousands of magnets that hold billions of particles in a beam narrow at very high speed.

The moment of this record, which resulted in an explosion of joy, can be seen, from 53 minutes in this video:

Relaunched for another four years, the LHC is already revolutionizing particle physics with a new pentaquark and a pair of tetraquarks never seen before.

Quarks, hadrons, atoms…

The name of these subatomic particles is derived from the term « quark », which designates an elementary particle of observable matter. The quarks constitute the hadrons, which include the protons and neutrons, themselves constituting the atoms with the electrons.

Quarks make up the “hadron” family of particles. The latter include in particular the protons (positively charged) and the neutrons (neutral), which themselves constitute the atoms, with the electrons (negatively charged).

The particles observed in Geneva are composed respectively, as their name indicates, of four and five quarks. That is to say more than protons and neutrons (three quarks).

Hence the qualifier « exotic » with which researchers at CERN have decked out these new particles.

Scientists are sometimes poetic: they have classified quarks into six “flavors”, namely: high, low, strange, charm, beauty, and truth.

The famous pentaquark is the first to be classified as « strange ».

“A magical moment”

The particles discovered this week are not as historic a breakthrough as the Higgs boson. They are not even the first “exotics” claimed by CERN. The good surprise, for the researchers who evoke “a magical moment”, comes mainly from the speed at which they obtained so much data:

The more analyzes we do, the more exotic hadron types we find.

Niels Tuning, physicist, LHC coordinator

On the strength of this first success, they explain that they expect to recover as much data during this third four-year round as during the first 13 years of LHC operation: « We are witnessing a period of discovery similar to that of the 1950s, when we discovered a ‘particle zoo’ that eventually led us to the hadron and quark model in the 1960s,” he adds:

We are creating the Particle Zoo 2.0

Niels Tuning

In search of the unfathomable dark matter

Decades of promising research, with the aim of better understanding the universe and its formation. Physicists hope to succeed in their quest for the famous « dark matter », which lies beyond the visible universe.

A “matter” which “would weigh” five times more than “ordinary” matter… but can only be “deduced”: indeed, it does not absorb, reflect or emit any light. So far, research has always failed. But the LHC could be a game-changer, as with the Higgs boson:

We will significantly increase the number of collisions and therefore the probability of new discoveries as well

Rende Steerenberg


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