Researchers last year thought they witnessed neutrinos traveling faster than light – overturning a fundamental tenet of Einstein's Theory of Special Relativity. Now, they're not so sure.
Neutrinos flitting through Earth faster than the speed of light? Not so fast.
A bum connection may have led to the stunning results from a physics experiment that showed subatomic particles called neutrinos traveling faster than the speed of light.
Researchers associated with the experiment, called OPERA, unveiled its initial results last September, along with a plea for other teams to see if they could independently verify the finding or hunt for glitches the OPERA team might have missed when it scrutinized the extraordinary results.
If the neutrinos did travel faster than light, the results would overturn a fundamental tenet of Einstein's Theory of Special Relativity, in which the speed of light in a vacuum is the ultimate speed limit for matter and energy.
The OPERA experiment is designed to study neutrinos – particles that carry no electrical charge and so rarely interact with matter. The particles are produced in nuclear reactions and during radioactive decay. A sophisticated neutrino detector, which sits inside a mountain in central Italy, records the arrival of pulsed beams of neutrinos generated in a particle accelerator at the European Organization for Nuclear Research (CERN), some 450 miles away.
In the brief announcement released this morning, the OPERA team noted that one possible glitch involved a bad connection along a fiber-optic line that feeds timing signals from GPS satellites to the ultimate stopwatch – the OPERA experiment's master clock. The master clock anchors the system that times the neutrinos' sprint from CERN to the underground lab at Gran Sasso.
Last fall's results had neutrinos showing up in Italy 60.7 billionths of a second faster than they would have appeared had they traveled at the speed of light. The connection problem could have led the clock to record a shorter travel time than the neutrinos in reality took, the team acknowledges.
Yet the researchers note another problem – a malfunction in an oscillator critical to keeping times synchronized – that could have led them to underestimate the neutrinos' speed.
The team has scheduled a new set of experiments set for May.
Although a good deal of skepticism remains over the initial results, it's not the first team to suggest the possibility that turbocharged neutrinos may exist.
Five years ago, researchers at Fermilab in Batavia, Ill., posted results indicating they'd found neutrinos traveling faster than light. But the extra oomph the neutrinos displayed was not deemed statistically significant enough to warrant a high-profile announcement.