In UA1 experiment

At CERN     1979-1982
In Helsinki 1982-1989

Main activity was: 
Event reconstruction and analysis in the UA1 central tracking detector.
The UA1 (Underground Area 1) experiment:
The UA1 experiment (1978-1989) was proposed in order to discover the intermediate vector bosons W and Z which are the mediators of the weak force. The CERN Super Proton Synchrotron (SPS) was upgraded for this purpose in order to be able to collect and accelerate antiprotons in the direction opposite to protons.

The protons and antiprotons collided head on with the total CMS energy of 540 and 630 GeV/c. By the end of 1982 about a million ppbar events were triggered by the UA1 apparatus and recorded on magnetic tapes corresponding to about one billion ppbar collisions in SPS. In this event sample five W->e+nu candidates were found and published. Later the UA2 experiment confirmed the discovery. UA1 made also the discovery of the Z particle in May 1984. In later stages of the experiment the detailed properties of the W/Z bosons and jet events were studied.