Prof. Antonio Ereditato, the head of an experiment that appeared to show subatomic particles travelling faster than the speed of light, has resigned from his post.
Prof. Antonio Ereditato oversaw results that appeared to challenge Einstein’s theory that nothing could travel faster than the speed of light.
Reports said some members of his group, called OPERA, had wanted Prof. Antonio Ereditato to resign.
Earlier in March, a repeat experiment found that the particles, known as neutrinos, did not exceed light speed.
When the results from the OPERA group at the Gran Sasso underground laboratory in Italy were first published last year, they shocked the world, threatening to upend a century of physics as well as relativity theory – which holds the speed of light to be the Universe’s absolute speed limit.
The experiment involved measuring the time it took for neutrinos to travel the 730 km (450 miles) from CERN laboratory in Geneva, Switzerland to the lab in Italy.
Prof. Antonio Ereditato oversaw results that appeared to challenge Einstein's theory that nothing could travel faster than the speed of light
Speaking at the time, Prof. Antonio Ereditato added “words of caution” because of the “potentially great impact on physics” of the result.
“We tried to find all possible explanations for this,” he said.
“We wanted to find a mistake – trivial mistakes, more complicated mistakes, or nasty effects – and we didn’t.
“When you don’t find anything, then you say <<well, now I’m forced to go out and ask the community to scrutinize this>>.”
Despite the call for caution, the results caused controversy within the world of physics.
If the findings had been confirmed, they would have disproved Albert Einstein’s 1905 Special Theory of Relativity.
Earlier this month, a test run by a different group at the same Italian laboratory recorded neutrinos travelling at precisely light speed.
Sandro Centro, co-spokesman for the ICARUS collaboration, said that he was not surprised by the result.
“In fact I was a little skeptical since the beginning,” he said at the time.
“Now we are 100% sure that the speed of light is the speed of neutrinos.”
So far, Prof. Antonio Ereditato has not commented on his decision to step down from his post.
A new experiment repeating the test of the speed of neutrinos has found that the subatomic particles do not travel faster than light.
Results announced in September suggested that neutrinos can exceed light speed, but were met with skepticism as that would upend Einstein’s theory of relativity.
A test run by a different group, ICARUS, at the same laboratory has now clocked them travelling at precisely light speed.
The results have been posted online.
The results in September, from the OPERA group at the Gran Sasso underground laboratory in Italy, shocked the world, threatening to upend a century of physics as well as relativity – which holds the speed of light to be the Universe’s absolute speed limit.
Now the ICARUS group, based at the same laboratory, has weighed in again, having already cast some doubt on the original OPERA claim.
Shortly after that claim, Nobel laureate Sheldon Glashow co-authored a Physical Review Letters paper that modeled how faster-than-light neutrinos would behave as they travelled.
In November, the ICARUS group showed in a paper posted on the online server Arxiv that the neutrinos displayed no such behavior.
The ICARUS group found that the neutrinos do travel at the same speed as light, within a small error range
However, they have now supplemented that indirect result with a test just like that carried out by the OPERA team.
The ICARUS experiment uses 600 tons – 430,000 litres – of liquid argon to detect the arrival of neutrinos sent through 730 km of rock from the CERN laboratory in Switzerland.
Since their November result, the ICARUS team has adjusted their experiment to do a speed measurement.
What was missing was information from CERN about the departure time of the neutrinos, which the team recently received to complete their analysis.
The result: they find that the neutrinos do travel at the same speed as light, within a small error range.
“We are completely compatible with the speed of light that we learn at school,” said Sandro Centro, co-spokesman for the ICARUS collaboration.
Dr. Sandro Centro said that he was not surprised by the result.
“In fact I was a little skeptical since the beginning,” he said.
“Now we are 100% sure that the speed of light is the speed of neutrinos.”
Most recently, the OPERA team conceded that their initial result may have been compromised by problems with their equipment.
Rumors have circulated since the OPERA result was first announced that the team was not unified in its decision to announce their findings so quickly, and Dr. Sandro Centro suggested that researchers outside the team were also suspicious.
“I didn’t trust the result right from the beginning – the way it was produced, the way it was managed,” Dr. Sandro Centro said.
“I think they were a little bit in a hurry to publish something that was astonishing, and at the end of the day it was a wrong measurement.”
Four different experiments at Italy’s Gran Sasso lab make use of the same beam of neutrinos from CERN.
Later this month, they will all be undertaking independent measurements to finally put an end to speculation about neutrino speeds.
The MINOS experiment in the US and the T2K experiment in Japan may also weigh in on the matter in due course – if any doubt is left about the neutrinos’ ability to beat the universal speed limit.
