The Oscillation Project with Emulsion-tRacking Apparatus (OPERA) is a scientific experiment for detecting tau neutrinos from muon neutrino oscillations. The experiment is a joint effort between the European Centre for Nuclear Research (CERN) and the Gran Sasso National Laboratory (LNGS). In September 2011, OPERA scientists said that they had seen neutrinos appear to travel faster than the speed of light. However, the scientists later found problems in their equipment which had caused the anomaly. The neutrino time of flight was consistent with the speed of light.
- "ABOUT OPERA". Retrieved 2011-10-25.
- Cho, Adrian (2011-09-22). "Neutrinos Travel Faster Than Light, According to One Experiment". Science. Archived from the original on 2011-11-06. Retrieved 2011-10-25.
- "OPERA experiment reports anomaly in flight time of neutrinos from CERN to Gran Sasso". CERN. 2012-06-08. Archived from the original on 2013-04-05. Retrieved 2015-01-15.