Faster-than-light neutrinos? New test confirms accuracy of experiment's initial measurement in flight time of neutrinos
After inviting the particle physics community to scrutinize their surprising neutrino time-of-flight measurements, a collaboration of physicists has rechecked many aspects of its analysis and taken into account valuable suggestions from a wide range of sources. One key test was to repeat the measurement with very short beam pulses from CERN. This allowed the extraction time of the protons, which ultimately lead to the neutrino beam, to be measured more precisely. The beam sent from CERN consisted of pulses three nanoseconds long separated by up to 524 nanoseconds. Some 20 clean neutrino events were measured at the Gran Sasso Laboratory, and precisely associated with the pulse leaving CERN. This test confirms the accuracy of OPERA's timing measurement, ruling out one potential source of systematic error.
