1974: The J/ψ meson was independently discovered by a group at the Stanford Linear Accelerator Center, headed by Burton Richter, and by a group at Brookhaven National Laboratory, headed by Samuel Ting of MIT.
In 1974, the J/ψ meson was discovered through independent efforts by researchers at SLAC and Brookhaven National Laboratory.  Burton Richter led the team at SLAC, while Samuel Ting headed the group at Brookhaven.