Canadian leads atom smasher particle search

A physicist at the University of Alberta is leading the newest experiment approved for Europe's Large Hadron Collider, searching for exotic subatomic particles resulting from high-energy collisions.

The experiment (called the monopole and exotics detector at the LHC, or MoEDAL) aims to find particles predicted to exist by certain theoretical models of how the universe works.

One of these particles is the magnetic monopole, a particle that instead of having a north and a south pole like every known magnet, has just a single pole.

"If we discover the magnetic monopole, this would fundamentally change physics right down to the level of the basic textbooks that first-year engineering students would look at, for example, when they look at electromagnetism," said James Pinfold, a physics professor at the University of Alberta and head of the MoEDAL project.

"It also will give us a potential for a lot of applications in the future," he said.

The magnetic monopole was first theorized to exist in the 1930s. Current theories in physics hold that it would only exist in nature under unusual circumstances, such as black holes or during the Big Bang.

Another particle that MoEDAL is designed to find is the stable massive particle, or SMP, which is predicted by a branch of theoretical physics called supersymmetry.

The Large Hadron Collider (LHC), a 27-kilometre underground particle accelerator beneath the French-Swiss border, is designed to recreate the energy levels that would create these particles by smashing protons together travelling at nearly the speed of light.

The MoEDAL detector will consist of 10 layers of plastic surrounding an existing detector at the LHC.

The idea is that any exotic particles generated by high-energy proton collisions in the LHC will punch holes in the plastic, and the holes, examined under a microscope, will reveal clues to the particles that caused them.

"When a heavily ionizing stable particle, such as a magnetic monopole or a massive stable supersymmetric particle, crosses the MoEDAL detectors, it produces damage in the plastic," said Pinfold, in a statement.

The particles passing through the detectors will produce characteristic marks, called etch-pit cones.

"Their size, shape and alignment yield accurate information about the charge and the direction of motion of the incident highly ionizing particle," said Pinfold.

CERN says the experiment is "small, cheap and quick to install, but its physics potential is huge."

None of the other six experiments at the LHC are designed to detect highly ionizing particles, so it acts as a complement to the rest of the work being done at the particle accelerator, CERN said.

The CERN Research Board approved the MoEDAL experiment at a meeting Dec. 2, 2009.

"If MoEDAL sees only a few candidates, it will be a very clear indication that something new and very interesting has been produced," said Pinfold.

The experiment is a collaboration among 25 researchers from nine scientific institutions in Europe and North America, including the University of Alberta and the University of Montreal. The first sheets of plastic for the MoEDAL detector have already been installed. Pinfold said the rest would be installed during a scheduled shutdown of the LHC in 2011.