In 1974, the independent discovery of the J/psi particle at SLAC and Brookhaven National Laboratory rocked the physics world, and entire textbooks had to be rewritten. Earlier this month, SLAC hosted a symposium to celebrate the milestone.
On Nov. 11, 1974, two research teams rocked the particle physics world when they announced they had independently discovered a new subatomic particle - the J/psi. The particle's existence called for a revision of what scientists had thought the universe was made of, and, practically overnight, entire physics textbooks had to be rewritten.
50 years later, on Nov. 8, the Department of Energy's SLAC National Accelerator Laboratory hosted a symposium to celebrate the 50th anniversary of the J/psi discovery, a key moment in modern particle physics now known as the November Revolution.
Back in 1974, one team including researchers from SLAC (then called the Stanford Linear Accelerator Center) and Lawrence Berkeley National Laboratory had discovered the particle while crashing beams of electrons and positrons into each other at SLAC's SPEAR ring collider. The other team, led by scientists from the Massachusetts Institute of Technology, had found the same particle at Brookhaven National Laboratory, where they smashed protons into a beryllium target. In 1976, SLAC's Burton Richter and MIT's Samuel Chao Chung Ting were awarded the Nobel Prize in Physics for their teams' discoveries.
The J/psi, a composite of a charm quark and its antimatter sibling, proved there was a previously unknown member in the family of quarks. The discovery was crucial in paving the way for our current understanding of the fundamental particles and forces in the universe, known as the Standard Model of particle physics. Today we know there are six types of quarks, including the fundamental building blocks of protons and neutrons found in everything we see around us.
Remembering the launch of a new era in particle physics
The Nov. 8 event drew a full house to SLAC's Kavli Auditorium, with additional viewers tuning in online to honor the milestone that redefined particle physics.