A journey underground
The measurements were made in the experiment CNGS (CERN Neutrinos to Gran Sasso), which literally sends particles through the earth from CERN to the OPERA experiment in the Gran Sasso observatory, located 720 km away in Italy. The particles in question are called muon neutrinos and have the unique property that they very rarely interact with other particles and can therefore move great distances through, for example, soil and rocks as if it was air. A 1300-ton detector captures them in Italy, after which, using very precise GPS measurements, it is possible to calculate the time they have taken to travel the distance from CERN to Italy, calculated down to an accuracy of just 20 cm.
The measurements made in the OPERA experiment at Gran Sasso provide the speed of the muon neutrinos down to an accuracy of less than 10 ns (0.000000001 seconds). The result shows that the particles move about 60 nano-seconds too quickly.
Break with the theory of relativity
"If the result turns out to not be related to measurement uncertainties, it is a violation of the theory of relativity, which has formed the basis for all physics since the beginning of the 1900s. According to Einstein’s theories, the speed of light is the upper limit for how fast particles, as we know them, can move. A time different of 60 nano-seconds gives a deviation that is well over 2000 km/h above the speed of light”, explains particle physicist Ask Emil Løvschall-Jensen, Discovery Center at the Niels Bohr Institute.
Tachyon a possible candidate
Ask Emil Løvschall-Jensen explains that if the result turns out to hold water, theoretical particle physicists are not entirely on bare ground. There is a proposal for a particle that can move faster than the speed of light. The so-called Tachyon, which got its name from the Greek word for quick, takhus, appears in several alternative theories. It has the unique property in that it acts with negative mass in the equations, which means that it will always move faster than the speed of light.
Whether there really is talk of a violation of the theory of relativity or an error in the measurements requires further investigation. By the same token, researchers behind the result are inviting a number of other researchers to find errors in the measurements at a conference later today at CERN. Whatever the result, physicists the world over are waiting in anticipation for the ruling.
Provided by Niels Bohr Institute
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