An Italian physicist at the head of a team behind a controversial experiment that appeared to contradict Albert Einstein's theory of relativity has resigned.
Antonio Ereditato stepped down as co-ordinator of the so-called OPERA experiment, Italy's National Institute of Nuclear Physics (INFN) said on Friday.
Ereditato's resignation came before a vote on a motion by some members of his OPERA team that he be removed after tests this month contradicted an earlier claim that the universe's speed limit had been broken.
OPERA's cautious but hugely controversial claim last year, that neutrinos may travel faster than the speed of light, would have upended aspects of Einstein's 1905 Special Theory of Relativity - a cornerstone of modern physics.
"I hope OPERA will find new unity and a new leadership to pursue its main target of observing the appearance of a new type of neutrinos," said Antonio Masiero, the deputy head of the INFN.
Masiero said another test on the speed of neutrinos, a type of sub-atomic particle, would still be carried out later this year to check OPERA's findings.
'The physicist of flop'
The experiment involved measuring the time it took for neutrinos to travel the 730km from the European Centre for Nuclear Research (CERN) laboratory in Geneva, Switzerland to the Gran Sasso Laboratory in central Italy.
A headline in Corriere della Sera called Ereditato "the physicist of flop".
Ereditato's team made the initial findings last September.
The neutrinos were timed at their departure from CERN's giant underground lab and again, after travelling through the Earth's crust, at their arrival at Gran Sasso in the Apennine Mountains.
To do the trip, the neutrinos should have taken 0.0024 seconds. Instead, the particles were recorded as hitting the detectors in Italy 0.00000006 seconds sooner than expected.
Knowing their findings would stir a storm, the OPERA team urged physicists to carry out their own checks to corroborate or refute what had been seen.
CERN said technical hitches may have skewed the initial measurements, something that critics of the findings said they had always suspected.