Experiments at the CERN ISR 1971-79
In 1971 I moved to Geneva to participate in an experiment at the ISR
at CERN within the British-Scandinavian collaboration. The collision
energies of the protons stored in the ISR were the highest in the world
for a number of years and many fundamental results were obtained at
this storage ring.
In an electron-nucleon deep inelastic scattering experiment at SLAC in
1969, the existence of electrically charged, point-like constituents
within the nucleon was demonstrated. Following this discovery the
first evidence for the strong interaction between the constituents
was given in high energy proton-proton collisions at the ISR, which
later led to the identification of the constituents as quarks and
gluons. The scattering between individual constituents within the
protons was expected to result in inclusive particle spectra with a
fall-off in transverse momentum which is much slower than the
approximately exponential behaviour that had been observed at small
transverse momenta, a behaviour which was also observed.
In 1974 the group started an experiment at the ISR Split-Field-Magnet,
which was a facility provided by CERN, consisting of a large magnet
equipped with a large number of multiwire proportional chambers
covering a large fraction of the solid angle. The spectrometer, which
had been used in the previous experiment, was moved to the Split-Field
Magnet as a complement to make particle identification at large angles
possible. The aim of this experiment was to investigate the structure
of the final states from high energy proton-proton collisions and, by
selecting high pT-reactions, we expected to gain more detailed
knowledge about collisions between the constituents of the colliding
hadrons.