Jack Steinberger - CERN

CERN

In 1968, Steinberger left Columbia University and accepted a position as a department director at CERN. He constructed an experiment there utilizing multi-wire proportional chambers (MWPC), recently invented by Georges Charpak. The MWPC's, augmented by micro-electronic amplifiers, allowed much larger samples of events to be recorded. Several results for neutral kaons were obtained and published in the early 1970s, including the observation of the rare decay of the neutral kaon to a muon pair, the time-dependence of the asymmetry for semi-leptonic decays, and a more precise measurement of the neutral kaon mass difference. A new era in experimental technique was opened.

These new techniques proved crucial for the first demonstration of direct CP-violation. The NA31 experiment at CERN was built in the early 1980s using the CERN SPS 400 GeV proton synchrotron. Aside from banks of MWPC's and a hadron calorimeter, it featured a liquid argon electromagnetic calorimeter with exceptional spatial and energy resolution. NA31 showed that direct CP violation is real.