Page 128 - UCT Research Report 2011

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UCT Research Report '11
“We have a discovery,” Rolf Heuer, the
director-general of Conseil Européen
pour la Recherche Nucléaire (CERN), the
world’s largest particle-physics laboratory,
based in Geneva, Switzerland announced
in early July. This vindicated considerable
investment from governments, research
organisations, universities and physicists
around the world; and marked a long-
awaited moment in physics.
After a 48-year search, a particle was observed by two of
the particle detection experiments (ATLAS – A Toroidal LHC
ApparatuS – and CMS – Compact Muon Solenoid) run at
the Large Hadron Collider (LHC), the most powerful particle
accelerator and one of the most complicated scientific
instruments ever built. Each collaboration confirmed the
formal discovery of a previously unknown particle, whose
weight and behaviour was consistent with a Higgs boson.
“This is the most exciting development in the last 30 years,
since the Z and W subatomic particles were observed in
the 1980s,” says Emeritus Professor Jean Cleymans, senior
scholar at the UCT Department of Physics and director of
the South Africa-CERN programme – a collaboration of
seven South African universities and research laboratories
participating in experiments at CERN.
“If this particle is the Higgs boson, it will complete
our understanding of the most fundamental and far-
reaching model of matter and force that mankind has ever
developed, the Standard Model”.
If this particle is not the Higgs boson it could open
the door for exploration to a completely new level of
understanding beyond the Standard Model. Either way,
this is big,” says UCT physics lecturer, Dr Andrew
Hamilton, speaking from CERN.
Smashing atoms
The idea that the building blocks, out of which everything
is made, are composed of smaller particles than had
previously been supposed gained momentum in the latter
part of the last century. The mechanism first proposed in
the 1960s, which later became known as the Standard
Model, explained how fundamental particles such as
quarks, gluons, electrons, and photons interact to build
the Universe we see around us; it explained the nature of
matter, but one element remained missing.
Without the Higgs, the mathematics underlying all this
simply would not add up.
“This discovery potentially completes the Standard
Model of particle physics,” says Professor Cleymans.
“If it is the Higgs, it is a defining moment in the history
and future of physics – it’s textbook material.”
The LHC uses two beams of protons travelling at almost the
speed of light, in opposite directions, in a superconducting
evacuated beam line of 27km circumference. The two
beams are magnetically manipulated to collide within
a detector – producing around 800 trillion multifarious
proton-proton collisions. The collisions provide individual
data points that, collectively, show the presence of what
is likely to be the Higgs boson.
Why particles matter
In particle physics, elementary particles give rise to the
world around us. The existence of the Higgs boson and
the associated Higgs field is the simplest of several
theories explaining why elementary particles have mass.
Without the Higgs boson, which is named after British
theoretical physicist Peter Higgs (who, at 83, was present
at the announcement in Geneva), no elementary particle
would have mass. And without this mass, there would be
no stars, no planets, and no atoms. No us, no matter.
What does it mean for the average Joe? In a theoretical
sense, the discovery contributes to the understanding
Solving the mysteries
of the Universe
“If this particle is the Higgs boson,
it will complete our understanding
of the most fundamental and far-
reaching model of matter and force
that mankind has ever developed, the
Standard Model.”
“This is one more example that UCT
is par t icipat ing in wor ld- leading
research. We are act ively and
meaningfully contributing to the
international scientific community.”