Those famous neutrinos that appeared to travel faster than light in a recent experiment probably did not, a group of scientists say, because they failed to emit a telltale type of radiation.
According to one physicist in the group, “it's hard to argue against” this latest objection to the controversial faster-than-light result produced by other scientists in the same Italian laboratory.
In a paper posted to the physics pre-print site arXiv.org, the group, which runs the ICARUS (Imaging Cosmic and Rare Underground Signals) experiment based at Gran Sasso Laboratory (LNGS) outside Rome, argues that any faster-than-light particles would be expected to emit a particular type of radiation as they traveled. Because they didn't detect any of this coming from the neutrinos — and because the particles didn't seem to be shedding energy in the form of undetected radiation — they must have been traveling at or below the speed of light.
Ultimately, the ICARUS group is arguing that the OPERA group, which ran the experiment that measured neutrinos making a trip from CERN Laboratory in Switzerland to LNGS in Italy 60 nanoseconds faster than light would have done, must have made some mistake in its timekeeping.