12 years of physics at OPAL
The OPAL experiment and the LEP collider started
operation in August 1989. Data taking finally ended on November 2, 2000.
(``
The first and the last OPAL event'').
The scientific evaluation of the data will continue for many more years.
The two phases of LEP operation were:
- LEP1 (1989-1995) where
millions of Z events were accumulated for high precision
measurements. In these events
the electron and the positron produce a single
Z boson .
- LEP2 (1996-2000) where the collision energy was
increased to make W+W- pairs,
and to search for possible new particles or physical effects
The links above lead to descriptions of the physics objectives of OPAL,
and to pictures of typical electron-positron
collision events.
An OPAL event
This event shows the annihilation of an electron and a positron.
In this interaction, a pair of heavy charged particles,
W
+ and W
-
bosons,
is produced. Each of them decays into two
quarks which are finally detected as particle jets
(rotating view) .
OPAL detector
A cut-away view of the OPAL detector
(photos from the installation).
The OPAL detector
The OPAL detector was a big general-purpose particle physics detector.
OPAL took its name from the detector description:
an Omni-Purpose Apparatus at LEP .
You can
take a tour
of the detector.
and the people working with it
The OPAL collaboration is a team of physicists and engineers who
designed, built and ran the OPAL detector, and who analyse the data
collected. Currently the collaboration consists of
about 200 physicists from
34 institutes in
Canada,
Germany,
Hungary,
Italy,
Israel,
Japan,
the United Kingdom and
the United States.