Gravitational Waves (Einstein, 1916 → LIGO, 2015)
Theory proposed:
Einstein predicted gravitational waves in 1916.
Initial response:
For nearly 100 years, every experiment failed to detect them.
Type II error:
The waves were real, but detectors (resonant bars, early interferometers) were too insensitive.
The true signal existed far below noise floor → repeated false negatives.
Later verification:
LIGO detected gravitational waves in 2015 with 5σ significance.
Neutrino Oscillations (1940s–1990s → 1998/2001)
Theory proposed:
Neutrinos change flavor (oscillate), which implies nonzero mass.
Initial response:
Decades of experiments found no evidence of oscillation.
Type II error:
The oscillations were too small, baseline too short, or statistics too low to detect.
Many early experiments concluded “no oscillations”—a false negative.
Later verification:
Super-Kamiokande (1998) and SNO (2001) confirmed oscillations.
This won the 2015 Nobel Prize.
The Higgs Boson (1964 → 2012)
Theory proposed:
Higgs mechanism predicts the Higgs field and boson.
Initial response:
Multiple experiments (LEP, Tevatron) failed to detect a Higgs across a wide mass range.
Type II error:
The Higgs signal was too faint and required massive luminosity.
The true Higgs existed at ~125 GeV, but early experiments lacked energy or statistics.
Later verification:
ATLAS and CMS at the LHC detected the Higgs in 2012 (5σ).