Page 4 - Eureka 2012

Cover story photo: Cern

“Carleton changed its focus. We were
compared to the event collisions that
Now, scientists will take more
looking at a tracking detector, then
are taking place this year at an energy
we ended up working on the forward took place at a total energy of 0.9 TeV, the heaviest boson ever found.
precise measurements to clarify
calorimeter, which is close to the of 8 TeV and next year’s expected whether the new particle is, in fact,
beam line and measures the energy increase to 14 TeV. the Higgs boson, or part of a larger
of streaming particles. It is exposed As the collisions intensify, scientists family of particles or something else
to some of the highest radiation rates must upgrade equipment and seek new entirely. Beyond that, physicists will
in the detector, so how we built it was technologies. “We have to start thinking examine the many theories about the
significant.” how our accelerators are going to run behavior of the Higgs and they expect
Parts were shipped from all over the in the future,” says Oakham. “Within the to find more exotic versions of the
world and, as Oakham points out, “This next decade, we are planning to run the particle. In the meantime, scientists at
is truly an international collaboration accelerator at six times the luminosity Carleton continue to work on upgrading
that transcends most of the traditional it runs at now.” detector equipment, and investigate
boundaries.” CERN first announced in December new technologies that will allow the
Carleton contributed two of these 2011 that it had made significant calorimeter to survive ever higher
detectors, starting with a prototype and progress in the search for the Higgs luminosities.
followed by years of testing. Oakham boson and suggested the experiments For more on Carleton’s ATLAS group,
points to the advantage of having had seen “tantalizing hints” that the visit www.physics.carleton.ca/atlas.
access to Carleton’s unique Science elusive particle was likely to have a Also check out the ATLAS website at
Technology Centre, highly experienced mass at the 124 to 126 billion electron www.atlas.ch, and CERN at http://
faculty and grants from TRIUMF, for volts (GeV) range. At that time, however, public.web.cern.ch/public/.
example, that allow engineers and the measurements were not strong On October 11, attend a public
technicians to work on the construction enough to claim a discovery. The July lecture at Carleton entitled “Discovery
projects. 4 announcement narrows the finding of the Higgs Boson: Mystery of Mass
A newer member of Carleton’s ATLAS down to around 126 GeV. This particle, Revealed”. Details available at www.
team is Thomas Koffas, who came to at the level of 5 sigma, is reported to be carleton.ca/science.
Ottawa in July 2011 after working as
a staff research physicist at CERN for
seven years.
Having been “at the heart of things”
for several years before joining the
Carleton team, Koffas admits the ATLAS
experiment was the more appealing.
“The ATLAS detector is well placed
and designed to search for new physics
at the LHC,” says Koffas, who was at
CERN when the first collision event
took place in 2008, and when the Higgs
boson discovery was made in July.
What happens in the LHC is the
acceleration of protons in opposite
directions. When the protons collide,
in effect re-creating the Big Bang in
miniature and the immediate after-
affects, scientists scramble to unravel
the resulting chaos. They analyze photo: James park
each of these “events” and record any
significant data.
The initial collision trials in the As members of the ATLAS particle physics experiment at the Large Hadron Collider at CERN,
27-kilometre underground accelerator Physics professors Gerald Oakham (left) and Thomas Koffas divide their time between their
Carleton labs and CERN’s underground facilities in Switzerland.

4 fall 2012