Wu was part of the team that discovered the J/ψ particle, providing evidence of the charm quark.
In early November 1974, Sau Lan Wu played a pivotal role in the discovery of the J/ψ particle while working as part of Samuel C. C. Ting’s team at Brookhaven National Laboratory. This discovery marked a significant milestone in particle physics, providing the first experimental evidence for the existence of the charm quark. Dubbed the "November Revolution," this breakthrough was instrumental in the confirmation of the Standard Model of particle physics, which categorizes all known subatomic particles. Wu’s contributions to this discovery were critical, highlighting her expertise and ability to work in highly collaborative international teams, despite the prevailing gender biases in science at that time.