Superluminal neutrinos: an OPERA in three acts

Abstract In September 2011 the OPERA experiment at the Gran Sasso Laboratory, Italy announced that they had evidence that the neutrinos in the CERN-to-Gran-Sasso (CNGS) beam line were travelling very slightly faster than the speed of light. If true this would have ranked among the most important discoveries of the 21st century. In the event it was not true and was rapidly discredited. This paper explains what the measurement entailed, the responses to it and the eventual explanation, and discusses whether the initial publication and the subsequent reactions were appropriate.