gold-plated event
n.— «Unfortunately, as Dr. Weinberg pointed out, ordinary collisions also produce showers of the same particles coming out, and so the game has changed. Once upon a time, physicists would look for what they called “a gold-plated event.” “You looked at a bubble chamber and saw tracks and decays,” Dr. Weinberg recalled. “You knew what you were seeing: ‘Aha! This is the omega minus,’” referring to a famous particle whose discovery clinched the case for quarks in 1964.» —“At Fermilab, the Race Is on for the ’God Particle'” by Dennis Overbye New York Times July 24, 2007. (source: Double-Tongued Dictionary)