Neutrinos Sent From CERN To Gran Sasso Respect The Cosmic Speed Limit, Speed Of Light Still Tops

At the 25th International Conference on Neutrino Physics and Astrophysics in Kyoto on June 8th, CERN Research Director Sergio Bertolucci presented results on the time of flight of neutrinos from CERN to the INFN Gran Sasso Laboratory on behalf of four experiments situated at Gran Sasso. The four, Borexino, ICARUS, LVD and OPERA all measure a neutrino time of flight consistent with the speed of light. 

This is at odds with a measurement that the OPERA collaboration put up for scrutiny last September, indicating that the original OPERA measurement can be attributed to a faulty element of the experiment’s fibre optic timing system.

The reconstruction of the core of a neutrino interaction at OPERA. The neutrino arriving from the left of the image has interacted with the lead of a brick, producing various particles identifiable by their tracks visible in the emulsion.

Credit: CERN

“Although this result isn’t as exciting as some would have liked,” said Bertolucci, “it is what we all expected deep down. The story captured the public imagination, and has given people the opportunity to see the scientific method in action – an unexpected result was put up for scrutiny, thoroughly investigated and resolved in part thanks to collaboration between normally competing experiments. That’s how science moves forward.”

In another development reported in Kyoto, the OPERA experiment showed evidence for the appearance of a second tau-neutrino in the CERN muon-neutrino beam, this is an important step towards understanding the science of neutrino oscillations.
Contacts and sources:
CERN