The group of scientists who shocked the world when they announced results of an experiment which suggested neutrinos may travel faster than speed of light have said the experiment will be repeated to address criticisms and allow review of the results.
BBC reports that Dr. Bergio Bertolucci, explaining the reason for rerun of the experiment, said it was important not to "fool around" given the revolutionary implications of the result. Rerunning the experiments will allow scientists rule out any errors that might have gone undetected in the previous experiment.
Dr. Bergio Bertolucci's team of researchers in Gran Sasso, Italy, had announced last month that neutrinos sent through the ground in the Opera (Oscillation Project with Emulsion-tracking Apparatus) experiment were measured as apparently traveling faster than speed of light. In the experiment, neutrinos sent from the CERN (European Organization for Nuclear Research) laboratory in Geneva, to Gran Sasso laboratory 732 kilometers away, appeared to have made the trip faster than expected, showing up in Italy a fraction of a second earlier than expected.
The journey, according to The Guardian, would take a beam of light 2.4 milliseconds, but in the Opera experiments, the neutrinos were calculated arriving at Gran Sasso, 60 billionths of a second earlier than expected. The speed of light is calculated at 299,792,458 meters per second, but the neutrinos apparently traveled at 299,798,454 metres per second.
BBC reports that in the experiment, protons fired from CERN in a "long pulse lasting 10 microseconds (10 millionths of a second) arrived 60 nanoseconds (60 billionths of a second) earlier than expected," calculating on the basis of the speed of light.
The results shocked the scientific world because, since Albert Einstein's proposal of Special Relativity, scientists have considered the speed of light the fastest speed at which anything in the physical universe may travel. This has lead some scientists receiving the results of Dr. Bergio Bertolucci's experiment with skepticism, saying the experiment incorporated some errors they failed to detect. One of the major objections to the results, in the series of scientific papers that followed, was raised by Sheldon Glashow and Andrew Cohen of Boston University. The scientists raised objections on the ground that neutrinos traveling faster than the speed of light will rapidly lose energy, but this effect was not detected by Bertolucci and his colleagues in the Opera experiment.
Several other scientists urged caution at the result. Professor Brian Cox, at the University of Manchester, according to The Guardian , said,
"If you've got something traveling faster than light, then it's the most profound discovery of the last 100 years or more in physics. It's a very, very big deal...It requires a complete rewriting of our understanding of the universe."
Professor Jim Al-Khalili at the University of Surry, expressed the opinion that "something was skewing the result." He said:
"If the neutrinos have broken the speed of light, it would overturn a keystone theory from the last century of physics. That's possible, but it's far more likely that there is an error in the data. So let me put my money where my mouth is: if the Cern experiment proves to be correct and neutrinos have broken the speed of light, I will eat my boxer shorts on live TV."
Other scientists have proposed possible explanations of neutrinos traveling fast than the speed of light. Dortmund University physicist Heinrich Paes, according to The Guardian, said it might be possible for neutrinos to take shortcuts through hidden extra dimensions of space. The physicist explained:
"The extra dimension is warped in a way that particles moving through it can travel faster than particles that go through the known three dimensions of space. It's like a shortcut through this extra dimension. So it looks like particles are going faster than light, but actually they don't."
BBC reported that after the result was announced, a meeting was held at CERN to deliberate on the result. The co-ordinator of the Opera experiment Antonio Ereditato, said it was left to the physics community to assess their result. Ereditato, addressing the meeting, said:
"Despite the large [statistical] significance of this measurement that you have seen and the stability of the analysis, since it has a potentially great impact on physics, this motivates the continuation of our studies in order to find still-unknown systematic effects...We look forward to independent measurement from other experiments."
In an interview with BBC, Ereditato explained:
"We tried to find all possible explanations for this...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.'"
Dr. Bertolucci, spoke with BBC, on the plan to rerun the experiment:
"In the last few days we have started to send a different time structure of the beam to Gran Sasso. This will allow Opera to repeat the measurement, removing some of the possible systematics."
In taking measurements, BBC reports the scientists used indirect methods based on methodology critics have faulted. The method involved superimposing the "neutrinos' arrival times on the protons' departure times over and over again and taking an average." Critics of the procedure say any wrong assumptions made in relation to the data could lead to misleading results.
Dr. Bertolucci and his team expect their new experimental design will address these criticisms. Bertolucci says the new design is more efficient. He explains: "For every neutrino event at Gran Sasso, you can connect it unambiguously with the batch of protons at CERN."
Scientists, such as Matt Strassler of Rutgers University, New Jersy, who had criticized the set up of the original experiment have expressed their approval of the new design. Professor Strasssler comments:
"It's like sending a series of loud and isolated clicks instead of a long blast on a horn; in the latter case you have to figure out exactly when the horn starts and stops, but in the former you just hear each click and then it's already over."
Dr. Bertolucci explaining the need to rerun the experiment, said:
"An experimentalist has to prove that a measurement is either right or wrong. If you interpret every new measurement with older theories, you will never get a new theory. More than a century ago, Michelson and Morley measured the speed of light in the direction Earth was moving and in the opposite direction. They found the speed was equal in both directions...If they had interpreted it using classical, Newtonian theory they would never have published."