Faster-than-light neutrino experiment replicates its earlier result

Nature : After the controversy caused by September’s superluminal neutrino announcement , the OPERA collaboration has now conducted a second experiment that replicates the findings of the first. Some scientists had expressed concern about the length of the proton pulses that CERN used to generate the neutrino pulses that it sent to Gran Sasso National Laboratory in the earlier experiment. They thought the pulses were so long that the OPERA researchers could not know whether individual neutrinos received at Gran Sasso corresponded to protons early or late in the proton pulse, creating uncertainty around their travel time, writes Eugenie Samuel Reich for Nature. Hence, the OPERA team members were asked to shorten the proton pulses in their second run. They generated 3-nanosecond-long pulses, compared with the 10.5-microsecond-long pulses produced in the earlier test, and have now recorded 20 events that show a similar level of statistical significance to the first set of results. The team has published its findings on the arXiv preprint server.