ROME—Two leaders of the OPERA collaboration, which stunned the world in September when it announced data suggesting that neutrinos could travel faster than the speed of light, have stepped down. The resignation of Antonio Ereditato as spokesperson and Dario Autiero as physics coordinator of the study followed a vote of no confidence, held yesterday by leaders of the individual groups within the collaboration, according to a source at OPERA who asked not to be identified. The vote came several weeks after it was revealed that the hotly debated result was probably caused by a faulty cable connection.
OPERA, based at the Gran Sasso National Laboratory in central Italy, measures the properties of neutrinos sent some 730 km through Earth's crust from the CERN laboratory near Geneva, Switzerland. The announcement that it had recorded these neutrinos arriving some 60 nanoseconds earlier than light appeared to violate Einstein's special theory of relativity. But in February, ScienceNOW reported that the early arrival time was probably due to a loose connection in a GPS system used to synchronize timing between the two labs.
Ereditato, who leads a group from the University of Bern, and Autiero, head of a group at the University of Lyon in France, had been the public face of the controversial study for the past 6 months, but apparently colleagues were unhappy about the way they had handled the results. Specifically, there was discontent about Ereditato's management, says the source at OPERA, while the opposition to Autiero focused on the measurement itself.
Some 16 group leaders voted against the pair yesterday, while 13 voted in their favor and several others abstained, the source says. Although collaboration rules specify that a two-thirds vote is needed to remove experiment leaders, the result meant that a majority wanted the pair gone. Ereditato apparently resigned his post a few minutes after the result of the ballot was known, whereas Autiero waited until today to step down. But it's unclear what their positions will now be within the collaboration.
Some collaboration members believe that the results, when first announced at a symposium at CERN on 23 September 2011, should have been presented more clearly as preliminary. They are also unhappy that more experimental checks weren't carried out before the announcement. "Once the seminar was done, OPERA should have undertaken a more extensive campaign of tests before submitting its paper to a journal," says Luca Stanco, leader of a group from the University of Padova in Italy, "including the famous cable test. Technical errors can happen to any collaboration. But we should have been more careful."
The collaboration now has to appoint a new spokesperson, although exactly when that will happen remains unclear. "I hope it won't affect the future of the experiment," Stanco says. "It is absolutely essential that we continue with the scientific program."
Antonio Masiero, vice president of Italy's National Institute of Nuclear Physics (INFN), which runs the Gran Sasso lab, has released a statement saying that he hopes the collaboration can "find unity and new leadership in carrying out its primary specific objective," the "oscillation" of muon neutrinos produced by CERN into tau neutrinos.
The statement added that "further and definitive" measurements of the velocity of neutrinos will be carried out by OPERA and three other experiments at Gran Sasso using a new finely pulsed beam sent from CERN at the end of April. Two of these experiments—Icarus and LVD—have recently reported results confirming that neutrinos cannot travel faster than light.
Neither Ereditato nor Autiero were available for comment today.