Particle physics experiments

Time, experiments and research of unknown physics

The 5 of July, beneath the suburbs of Geneva, Switzerland, the world’s largest particle collider will power up and begin collecting data again. And what they might discover has the potential to explode particle physics.

After nearly four years of shutdown, extended by Covid-induced delays, the Large Hadron Collider (LHC) is about to launch its third series of experiments: called, succinctly, Run 3. CERN will commemorate the launch with a livestream at 10:00 AM Eastern Time.

Physicists are pinning high hopes on Run 3. They hope to unlock new particles and mechanisms they’ve never been able to see. Recent research in physics has unveiled a possible fifth force and challenges for the standard model of physics. Execution 3 could

What does the Large Hadron Collider do?

The LHC is a particle collider. The name accurately describes what the LHC does: it smashes particles – usually protons, but it can also collide with larger particles that physicists call “heavy ions”. Typically, this means lead ions, the heaviest non-radioactive element.

To do this, the LHC first launches two particle beams into its ring, traveling in opposite directions. They turn in circles, accelerated and guided by powerful electromagnets, until they reach a speed very close to light. Then, after picking up speed, they collide head-on.

The ALICE experiment at CERN, which deals with large ions. Ronald Patrick/Getty Images News/Getty Images

These collisions cause the innards of fast particles — the smallest particles that function as their building blocks — to come apart. Some clash. And in the high-energy, high-temperature, extreme-high conditions of a collision, all kinds of strange particles can fly out of the woodwork.

Scientists study the detritus that remains. Their highly sophisticated detectors can scour the debris and find the streaks, streaks and fingerprints that all those particles leave behind.

Objective of the Large Hadron Collider

Smashing particles together seems like a crude way to get to know them: a bit like smashing complex electronic devices together and hoping to learn how they work from the mangled components that remain. But it’s the best way for physicists to examine the quantum world, at scales millions of times smaller than those of atoms.

But in these collisions, many of these particles are ghosts, barely interacting with the world or for fractions of a second. As a rule, they go unnoticed, even if you look at them with very powerful detectors. But scientists can find the telltale signatures of these particles in the high-energy soup that momentarily emerges inside a particle collider like the LHC.

Improvements made to the LHC during the shutdown have increased its energy, giving it even more power to unveil this subatomic world.

Large size of the hadron collider

The LHC is a juggernaut. It is housed in a circular tunnel 27 kilometers (17 miles) in circumference and 4 meters (13 feet) wide, buried several stories underground. From CERN headquarters on the outskirts of Geneva, this tunnel passes under the towering Jura Mountains, along the rolling Franco-Swiss border, and back.

The LHC is so big because, with more circumference for a particle beam to accelerate, the particles can get closer and closer to the speed of light and, therefore, carry higher energies. With higher energies, physicists can see more particles as the beams collide.

As massive as the LHC is, scientists aren’t afraid to dream even bigger. If some scientists are successful, the LHC will have a future successor – a so-called future circular collider – which is almost four times the circumference.

The LHC computing grid, responsible for processing the petabytes of information produced by the experiments.FABRICE COFFRINI/AFP/Getty Images

Discoveries of Large Hadron Colliders

Perhaps the most publicized LHC discovery to date is the Higgs boson. According to particle physics, this ghostly particle is a product of what is called the Higgs field, which gives mass to certain particles, the W and Z bosons. These particles guide the weak nuclear force that governs certain forms of radioactivity.

By finding the Higgs boson, particle physicists were able to confirm that much of their theory of how the universe works on tiny scales was correct. But the Higgs boson is very unstable, and observing it has to deal with the fact that it will decay almost instantaneously.

The Higgs boson was first proposed as far back as the 1960s, and since then scientists have searched for it for decades until it was finally discovered in 2012 at the LHC. In fact, the quest for the Higgs boson was one of the reasons the LHC was built in the first place. Earlier particle colliders did not have the energy to find it.

Even though scientists have found a Higgs boson, they don’t fully understand its properties. Doing this is on their wish list.

What are the new experiences of the Large Hadron Collider?

There are no *new* experiments per se – but they build on existing ones in search of unknown physics.

The LHC is not just a great experiment. It actually hosts several experiments. Each is looking for different particles or looking at different physics. Each has its own detector located somewhere along the accelerator loop. Each is supported by hundreds of scientists around the world.

There are four big ones. ATLAS and CMS are “general purpose” experiments, examining a wide range of particles that pass through the scrutiny of their respective detectors. Both of these experiments found the Higgs boson.

Illustrations of CMS and ATLAS detectors. All About Space Magazine/Future/Getty Images

ALICE hopes to study a novel phase of matter known as “quark-gluon plasma,” where atoms literally melt into a super-hot soup. Cosmologists believe that quark-gluon plasma dominated the universe for a brief time early in its history.

LHCb (short for “LHC beauty”) aims to examine a particular particle, called the beauty quark. Scientists believe the beauty quark can teach them more about the differences between matter and its oppositely charged destructive twin: antimatter. When matter and antimatter touch, they annihilate. The Big Bang should have created matter and antimatter in equal amounts, but it seems to have created an excess of matter, the matter that surrounds us. This imbalance has no explanation.

There are several small experiments, many of which look at other specific particles or other elements of physics.

What do CERN scientists hope to discover?

For decades, particle physics has lived and died by what is known as the Standard Model. It’s a diagram that neatly lays out the fundamental particles of the universe – 17 of them – and how they interact with each other. It governs three of the four fundamental forces in the universe: the strong nuclear force, which holds particles together inside the nucleus of an atom; the weak nuclear force, which guides certain forms of radioactivity; and electromagnetism.

For decades, particle physics seems to have almost always obeyed the predictions of the Standard Model — almost.

Particle physicists are increasingly convinced that the Standard Model is not everything. There are a few curiosities that the standard model does not satisfy. For example, the model does not respond to the fourth fundamental force: gravity. Nor has it (so far) yielded a satisfactory culprit for dark matter, which is more than five times more abundant than “normal” matter.

Some of these unanswered questions have led scientists to suspect that there is a fifth fundamental force lurking somewhere. One idea is that this fifth force is somehow related to dark energy, a mysterious form of energy that seems to cause the universe to accelerate.

Some experiments have hinted at particles beyond the Standard Model, possibly carriers of physics beyond the current understanding of scientists.

Recently, scientists poring over old data from another particle accelerator at Fermilab in suburban Chicago discovered that one particle, the W boson, has a higher mass than expected. It sounds minor, but it’s a serious violation of the standard model. Physicists hope the LHC can help them test this.