One of the universe’s biggest mysteries, dark matter, may finally be solved when the Large Hadron Collider (LHC) returns to activity on July 5.
Matter of unknown nature makes up more than three-quarters of the universe, but scientists still have no idea what it is.
Now, the world’s most powerful particle accelerator has been specially updated to help find that answer. The LHC is part of the European Organization for Nuclear Research, known as Cern, on the Franco-Swiss border outside Geneva.
If scientists manage to unlock the secrets of dark matter, it won’t be the first time the LHC has made a breakthrough.
This month marks the tenth anniversary since researchers made one of the biggest discoveries of the 21st century: the Higgs boson. Without this particle and its associated field, nothing in the universe as we know it would exist.
On July 5, the LHC will begin operating at its highest power as it prepares for its search for dark matter.
Long journey
British particle physicist Clara Nellist is part of the team hoping to track down dark matter — but her journey to becoming a top scientist hasn’t been an easy one.
“We didn’t have a physics teacher at my school,” she says.
Because of this, she was unable to expand her knowledge of physics and had to look elsewhere to study in order to keep her dream of becoming a scientist alive.
“I had to travel twice a week to go to another school for these classes. [de física].”
Her pre-university physics exam, for example, she took alone in her own school.
Despite obstacles, Nell studied at the University of Manchester in England. Later, while researching her doctorate, she began working on experiments at the LHC.
She was at CERN in 2012, when the famous announcement about the Higgs Boson was made.
“I slept outside the auditorium to get a seat in that room and to hear the historic moment that our director general announced that we had discovered this new particle.”
“The memory of this discovery drives me to work on these teams to try to find the next big discovery.”
The discovery of the Higgs boson was reported all over the world’s press.
“The Higgs boson is a really special particle because it’s related to how other elementary particles gain mass.”
“When particles interact with the Higgs field, they gain mass and the Higgs boson is what we can find in our experiments to show that the Higgs field exists.”
The Higgs field is an energy field that gives mass to other fundamental particles such as electrons and quarks.
The Higgs boson has been nicknamed the “God particle” because the process of gaining mass has been compared to the Big Bang, the origin of the universe.
better and more powerful
“The last few years have been really exciting because we’re updating and repairing our accelerators and the experiments at the LHC,” says Nellist.
With the upgrade, the LHC becomes more powerful — more particles will collide, and more collisions translate to more data to analyze.
The LHC uses an incredible amount of energy — annually, CERN uses enough electricity to power a small town, or about 300,000 homes a year.
Some of that energy is used to accelerate protons to nearly the speed of light — fast enough that when they collide, they split into even smaller particles.
“Two of the major upgrades to the LHC are that we got a higher energy, so this is record collision energy,” says Nellist.
“And we’ve also improved the crossover angle at which protons collide inside the detectors, and that increases the likelihood that two protons will interact, which increases the amount of data we can collect.”
dark matter mystery
At CERN, they hope that all this data will help them unlock the secrets of dark matter.
“Dark matter makes up about 80 to 85% of our universe and gets its name because it doesn’t interact with light and therefore we can’t see it,” says Nellist.
“The interesting thing is that we don’t really know what it is.”
So far, scientists have only observed indirect evidence of dark matter. A definitive and direct detection of dark matter particles remains elusive.
There are several theories to explain what this particle might be like. One of the favorites among scientists around the world is the WIMP, or Weakly Interacting Massive Particle.
“It’s still a big mystery, so we’re trying to see if it can be created in our experiments.”
For scientists, it’s one of the most frustrating puzzles about our universe — that we still don’t know what it’s made of.
“I’d love to find out what dark matter is, in my career. That’s my personal goal. Otherwise, we’ll see what secrets the universe has for us.”
– This text was originally published in https://www.bbc.com/portuguese/geral-62036160
