J/psi particle

A compound of J, ψ (ps) (psi), and particle. The particle was discovered independently in 1974 by two research groups, leading to the "November Revolution" in particle physics.

The group led by Samuel Ting at Brookhaven National Laboratory proposed the name J, reputedly because the shape of the Chinese character for Ting (丁) resembles a J, though Ting also cited the symbol for electromagnetic current, jμ(x), as a reason.

The group led by Burton Richter at SLAC proposed the name ψ (psi). Richter initially preferred "SP" (for the SPEAR accelerator), but chose "psi" as it contained "SP" in reverse order and was the only remaining Greek letter deemed suitable; coincidently, the particle's decay pattern in spark chambers resembled the letter ψ.

The compromise name J/ψ was adopted to acknowledge both discoveries.