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Awarded in equal shares to Carlo Rubbia and Simon van der Meer for decisive contributions to the project that discovered the $W$ and $Z$ particles mediating the weak interaction.^[ref]

Simon van der Meer was an electrical engineer whose development of stochastic cooling made dense antiproton beams available for collider experiments. The method reduces the spread of particle motion in phase space, allowing beams produced over many cycles to be accumulated.^[ref]

A pickup senses an electrical signal from particles passing through a storage ring. After amplification and an appropriate delay, a downstream kicker applies a corrective force. The timing connects the measured deviation with the returning particles; the signal from each particle is mixed with contributions from others, so gain and noise determine the net cooling. This turns high-speed feedback electronics into a tool for controlling a particle distribution.^[ref]

Simon van der Meer's stochastic cooling uses measured beam fluctuations, a pick-up, amplifier and timed kicker. Finite samples supply the signal; other particles and electronic noise contribute unwanted kicks. Delay and oscillation phase must make the correction oppose the sampled deviation.^[ref]

This active system dissipates energy; it is no one-particle Maxwell's demon individually tracking antiprotons. The stochastic cooling variance model isolates the tradeoff.