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Carlo Rubbia helped establish the experimental existence of the massive carriers of the weak interaction, the W boson and Z boson. His lecture explains how proton–antiproton collisions produced candidate events whose energetic leptons and reconstructed kinematics distinguished them from abundant hadronic backgrounds. For decays involving a neutrino, missing transverse momentum supplied information about an unseen particle. The discovery connected electroweak theory with identifiable short-lived particles in a collider detector.^[ref]

A physicist.^[ref]

The Super Proton-Antiproton Synchrotron used the converted SPS ring for counterrotating proton and antiproton beams. In the discovery running, two $270\mathrm{GeV}$ beams provided $\sqrt{s}=540\mathrm{GeV}$, unlike a stationary-target collision at the same incident energy. Antiproton production, accumulation and stochastic cooling supplied the collisions used in the W and Z discovery experiments.^[ref]

Why can opposite electric charges share the bending magnets? Reversing both $q$ and velocity $\mathbf{v}$ leaves the Lorentz force $q\mathbf{v}\times \mathbf{B}$ unchanged at a given point. Both circulating species can therefore bend toward the same ring center in the same magnetic field, with equal magnetic rigidity magnitudes. This argument explains the bending geometry; actual injection, focusing, timed acceleration and collisions still require a complete particle accelerator system.

A W boson decay can leave one visible charged lepton and a large missing transverse momentum; a Z boson decay can instead supply two visible leptons whose four-momenta determine an invariant mass. The two signatures answer the same existence question with different missing information. The electroweak unification history recognized by the 1979 Nobel Prize in Physics predates these 1983 observations: the W boson and Z boson were predictions to test, rather than particles first proposed in 1983.

The Super Proton-Antiproton Synchrotron stored counterrotating proton and antiproton beams; stochastic cooling made accumulation of the scarce antiprotons practical. Carlo Rubbia's 1984 lecture describes track reconstruction in a large drift chamber inside a magnetic field, surrounded by segmented particle calorimeters. Their nearly complete angular coverage allowed an imbalance test for unobserved neutrinos.^[ref]