The European Organization for Nuclear Research, CERN, celebrates its
50th anniversary on 29 September. A sort of United Nations of physics,
with numerous European member states and many more non-European affiliates,
the Geneva-based CERN has been the site of several notable achievements
and discoveries in the area of elementary particle physics. These include
the observation (1973) of neutral-current weak interactions, a type
of scattering event in which two particles interact via the interchange
of a heavy neutral boson force particle; later the production (1983)
of that same force particle, the Z boson, and its charged cousins, the
W+ and W- bosons; the creation of the World Wide Web (1990) as a means
of transferring huge amounts of data; hints of a novel kind of new nuclear
matter (perhaps quark-gluon plasma) amid high-energy, heavy-ion collisions
(2000); and creation of slow-moving anti-hydrogen atoms (2002).
The Large Electron Positron collider (LEP), recently retired, was the
scene of additional high-precision measurements of the weak nuclear
force and other aspects of the standard model. LEP is lending its 27-km-round
tunnel for the construction of the Large Hadron Collider (LHC), in which
two beams of 7-TeV protons (or heavy ions) will be collided head on.
Out of the violence of these smash-ups, physicists hope to achieve such
long-sought goals as producing the Higgs boson and various members of
a family of supersymmetric particles (consisting of boson cousins of
known fermion particles and fermi cousins of known boson particles),
and maybe even discern evidence for the existence of extra dimensions.
Completion is expected in the year 2007. (See http://intranet.cern.ch/Chronological/2004/CERN50/)