Reprinted from Waves and Packets, April 7,2012 edition
With the March 15 paper of the ICARUS group claiming no advance effect for their (seven) neutrino events, it seems the urgency and interest in this matter is dwindling. OPERA spokesperson Antonio Ereditato and experimental coordinator Dario Autiero have announced their resignations, following a controversial vote of “no confidence” from the collaboration’s other leaders. Waves and Packets has asked three distinguished physicists what they think the lessons learned are from the entire episode.
“It is misconception that Einstein’s special theory of relativity says that nothing can travel faster than the speed of light. For example, electrons can travel faster than the speed of light in water. This leads to a phenomena known as Cherenkov radiation which is seen as a blue glow in nuclear reactors. In addition, for a long time it’s been speculated that subatomic particles known as a tachyons might exist. Tachyons are theoretically predicted particles that travel faster than the speed of light in a vacuum and are consistent with Einstein’s theory of relativity. For ordinary subliminal particles light acts as a barrier from above. That is ordinary matter cannot be accelerated to the speed of light. For superluminal tachyons light acts as a barrier from below. That is to say that tachyons cannot be decelerated to the speed of light. It has been conjectured that tachyons could be used to send signals back in time. To date tachyons have not been observed experimentally.” Ronald Mallett, University of Connecticut-Storrs
“I think the first thing the whole episode indicates is that there is still enormous public interest in our field. The need to explore is still felt keenly so we need to be clear that announcing results, even controversial ones, should be respected by scientists if proper peer review of those results has been performed. It also points out the absolute necessity of following through on external checks. Public review of the scientific process is not a bad thing nor is showing some humility and skepticism even about ‘sacred’ principles like special relativity. Episodes like this one give us the opportunity to address misconceptions like those surrounding the connection between special relativity and the speed of light. Showing fallibility doesn’t weaken us as long as we remain appropriate demanding of ‘extraordinary proof’ for “extraordinary results.” Larry Gladney, University of Pennsylvania
“I can think of two positive remarks to be made. The first is that, given an information leak from someone familiar with the OPERA experiment to Science magazine, the OPERA Collaboration did the right thing in going public with the information they had at hand. In the spirit of good science, they nearly begged other experiments to validate or invalidate their working hypothesis of superluminal neutrinos. It now appears that invalidation was in order, as reported by the ICARUS experiment. Over the next several months, we may anticipate half a dozen experiments on three continents providing further measurements of neutrino speed; new data will also be forthcoming from the OPERA and ICARUS experiments. My second positive remark is that many of us have been pushed by the OPERA claim to examine the deeper meaning of Special and General Relativity. While paradoxes, such as superluminal travel with inherent negation of cause and effect, are mathematically consistent with Einstein’s equations, they generally are hidden behind horizons, or require invocation of new physics such as negative energy, extra dimensions, sterile neutrinos, etc. It has been fun and educational to think about the possibilities. Any opportunity to explore a guarded secret of Nature must be seized upon. It unfortunately appears now that superluminal neutrino travel may not be one of Her guarded secrets.” Thomas Weiler, Vanderbilt University
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