50 years ago, physicists thought they found the W boson. They hadn’t

Excerpt from the August 21, 1971 issue of Science News

an computer illustration of streaks of yellow bouncing around in loops - showing how the debris from a proton-antiproton collision moved. the straighter path of a high-energy electron is also shown

An experiment at CERN in 1982 captured this image depicting debris from a proton-antiproton collision. The path of a high-energy electron (indicated by a red arrow, bottom right) detected in the smashup’s aftermath was consistent with the expected decay of products of a W boson.


August 21, 1971 cover of Science News

The W particle may have been foundScience News, August 21, 1971

Physicists distinguish four different kinds of force by which objects in the universe act upon each other: the strong nuclear force, the weak force, electromagnetism and gravity. The developed theory of particle physics outfits each force with a so-called intermediate particle.… Now, from an abandoned silver mine at Park City, Utah, comes strong evidence of the existence of the weak-force quantum, known as the … W particle.


The “strong evidence” for this W particle, or W boson, fell apart under additional scrutiny. Physicists with CERN near Geneva finally caught the boson about a decade later (SN: 2/5/83, p. 84). Besides helping mediate the weak force, which governs certain types of radioactive decay, the W boson has also helped scientists catch the Higgs boson (SN: 7/28/12, p. 5). Weighing the W boson narrowed down the Higgs’ mass range, making the Higgs easier to look for. Physicists continue unraveling W boson mysteries, such as how the particles form and whether more massive versions exist.

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