Technology & Science

Canadian teens hunt subatomic particles at CERN after winning global contest

Cambridge, Ont., high school students 1st team from Americas to win Beamline for Schools

Emily Chung - CBC News

September 28, 2017

A group of Cambridge, Ont., students are using a high-energy beam of protons from a device called the proton synchrotron at CERN to look for fractionally charged elementary particles, which have never been observed by physicists. (CERN)

A group of teenaged students from Cambridge, Ont., is hunting for new subatomic particles at the home of the world's largest atom-smasher, the Large Hadron Collider.

The six boys and seven girls of the "Charging Cavaliers" are running experiments this week among the monitor-lined control rooms and powerful high-energy beams and detectors at CERN, the European Organization for Nuclear Research, near the French-Swiss border.


The Charging Cavaliers attend a safety demonstration at CERN's Large Hadron Collider mock-up tunnel. The students are currently running experiments from CERN. (CERN)

It's a big step up from the pencils, cups and string they had previously used for experiments in their high school physics classes.

"It's a once-in-a-lifetime experience," said team member Mariam Ibrahim, 18, in a phone interview from CERN.

The students hope to find something that particle physicists with PhDs and high-tech equipment have been unable to find after decades of searching — elementary particles that have a fractional charge, like +½ or -⅓, unlike familiar particles like the proton (with a charge of +1) and electron (with a charge of -1).

'If we do find something, we're opening a whole new door on particle physics.' - Denis Jacques, physics teacher

While studying at École secondaire catholique Père-René-de-Galinée this past spring, the students entered CERN's fourth annual Beamline for Schools competition, which invites high school students from around the world to propose experiments that could be run at CERN and produce a video to explain it.

180 teams

The Charging Cavaliers' proposal beat out 178 other teams from 43 countries. They were one of two schools that won the chance to run their experiment at CERN. The other winners this year were from Liceo Scientifico Statale T.C. Onesti in Fermo, Italy.

While particles like protons and neutrons are thought to be made up of smaller particles that have fractional charges called quarks, those particles have never been directly observed or found on their own outside of bigger particles like protons and neutrons.

Team leader Paul McKarris, 18, used to live in Switzerland within walking distance of CERN and heard about the Beamline for Schools competition while interning there. When he moved to Canada for his last year of high school, he was keen to enter. So he started a physics club at his new school and recruited physics teacher Denis Jacques and family friend James Pinfold, a University of Alberta physicist, to help.

McKarris, who is now in his first year of mathematical physics at the University of Waterloo, had read that fractionally charged particles had never been found.

"So I was like, 'Well, it may be a good idea to look for them.'" he said. "There's nothing that says they don't exist."

Team leader Paul McKarris, 18, read that fractionally charged particles had never been found, so he decided it might be a good idea to join the search. (C. Lise Knapp/École secondaire catholique Père-René-de-Galinée)

Still, there's a good chance the students won't find anything, acknowledges Denis Jacques, the teacher who worked with the students on their proposal and accompanied them to CERN.

"But if we do find something, we're opening a whole new door on particle physics," he said. "We would be contenders for the Nobel prize, as much as people don't believe us."

The students aren't using the Large Hadron Collider, CERN's record-breaking atom smasher, itself — that would be "much too powerful (and too expensive)," said Markus Joos, project leader for CERN's Beamline for Schools, in an email.

Instead, they're taking a high-energy beam of protons from a device called the proton synchrotron. They'll fire that at an iron target to create a collision. The bits that come off that have a charge of +1 or -1 one will be diverted with a magnet, said team member Ibrahim, who is studying biomedical sciences at Guelph.

That should leave behind any particles with a fractional charge, which will be directed into two particle detectors called scintillators that the team brought over from Canada.

On Tuesday, the students were still working on getting the beam calibrated just right and testing the detectors. During the past few days they had struggled with unexpected, unwanted signals — what scientists refer to as "noise."

But with some problem solving, things now seem to be on the right track. The students will be running their experiment until Oct. 2.

McKarris said that even if he and his teammates don't find anything, it will still have been an amazing experience. He recalls the first time the invisible proton beam was turned on for the experiment.

"It was just like a moment of, 'Wow, this is actually happening. What was written in paper is now real.'"

The charging cavaliers pose at the airport before leaving for CERN. They'll be running their experiment there until Oct. 2. (Lise Knapp)

The Beamline for Schools winners from Canada and Italy pose with their teachers and CERN staff in front of an LHC dipole magnet on the terrace of CERN. The contest got 180 entries from 43 countries. (CERN)

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