By Sam Reynolds
CERN scientists make inroads on studying trapped antimatter
In a groundbreaking experiment at Europe’s CERN laboratory, a Canadian-led team directed by an SFU researcher has trapped anti-matter particles of hydrogen for long enough to study them in hopes to finally discover the secrets of the mysterious atoms.
“This is the first time that anyone has ever interacted with an antimatter atom,” wrote Mike Hayden, an SFU physics professor and lead in the project, in the journal Nature.
The team was able to observe the “atomic fingerprint” of an antimatter particle, a major breakthrough as scientists previously struggled to explain why it existed at all with the data that they had.
“We’ve performed a measurement. We’ve tried to look for what you might call a sign of a fingerprint of this atom,” Hayden told CBC News. “You could think of it like trying to communicate with this atom, or manipulate it.”
Other Canadian researchers involved with the project are from the universities of Calgary, Victoria, York University, and TRIUMF, Canada’s national particle physics lab based at UBC.
While antimatter may be familiar to most as science fiction lore, researchers have long attempted to produce it in a laboratory and hold it steady enough for observation. First discussed in the 1880s by British physicist William Mitchinson Hicks, the term was coined in 1898 in the journal Nature. A formalized paper was published in 1928 by Proceedings of the Royal Society of London, and antimatter was first discovered in a laboratory, as anti-electrons, or positrons, four years later.
Antimatter is made up of particles that have an opposite charge from matter, with the remaining characteristics remaining the same. When matter and antimatter collide, both particles are destroyed by the energy reaction that occurs as a result.
This destruction makes antimatter particularly challenging to observe, as matter — which annihilates it on contact — makes up the majority of the Universe. In order to prevent the contact of matter and antimatter to allow observation, Hayden and his team used a device that suspended antimatter in a magnetic trap, keeping it away from the sides of the containing unit which is made of matter.
This device was the product of a CERN based group called the ALPHA collaboration, of which SFU researchers were also involved.
To trap and observe antimatter researchers combined anti-protons with anti-electrons to form a cloud of anti-hydrogen atoms. Last year, the team managed to trap antimatter for an unprecedented 16 minutes.
According to the paper published in Nature, the team then exposed these anti-hydrogens to high frequency radio waves while changing the strength of the magnetic trap to try and force them to escape, tracking their movement and patterns as they did.
“We end up getting images of tracks left by these particles, and we can lay these tracks all out and figure out where the common origin is, where did this little explosion occur,” Hayden said in an interview with the National Post. “What we see, of course, is that sure enough it comes right from the outside edge of our trap, where we expect them to come from.”
Scientific literature suggests that after the big bang, matter and antimatter were being rapidly created at a frenzied space as the universe expanded and cooled. Thus, having an outline of the “atomic fingerprint” as well as observations of an antimatter particle would give scientists new clues to the genesis of the universe.
“One of the reasons we want to study the spectrum of the antihydrogen atom is to look for clues that might shed light on a baffling mystery,” Hayden said to The Peak. “Everything we know about physics suggests that large quantities of matter and antimatter should have been created in the aftermath of the big bang”.
“So what happened? Where did the antimatter go? Trying to get to the bottom of this mystery is enormously important in physics and astronomy.”
“If we can see any small difference (between hydrogen and anti-hydrogen), maybe we can get some idea of why there is this preference for matter in the universe,” Tim Friesen, another Canadian researcher involved with the project said to the Calgary Herald.
“This experiment opens the door to precision comparisons of matter and antimatter,” said SFU PhD candidate Mohammad Ashkezar in a press release. “Eventually measurements like this will reveal clues that may help solve one of the deepest mysteries in particle physics.”
