Science and Technology Facilities Council
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New results fail to rule out 'faster than light' neutrinos
New results (18 November 2011) from the OPERA collaboration based at the Gran Sasso Laboratory in Italy support earlier experiments that suggested that neutrinos can travel faster than the speed of light.
The initial results released on 23 September (link opens in a new window)caused an international sensation because they could dismiss one of the key assumptions that underpins modern physics. Since then scientists around the world have been scrutinising every aspect of those experiments looking for clues that might explain the perplexing results.
The latest OPERA results have ruled out some of the possible errors identified by the international particle physics community. By sending narrower bunches of neutrinos from CERN to Gran Sasso, but with more time between bunches, the team has been able to make more accurate measurements of velocity. 20 clean neutrino events were measured at Gran Sasso that could be precisely associated with the pulse leaving CERN. The new measurements do not change the initial conclusion that the neutrinos were travelling faster than the speed of light. Nevertheless, the observed anomaly in the neutrinos' time of flight from CERN to Gran Sasso still needs further scrutiny and independent measurement before it can be refuted or confirmed
Like the initial results, the OPERA collaboration has published its latest findings at an early stage to make them available for wider scrutiny.
Professor Dave Wark, STFC Director of Particle Physics and leader of the UK group on the T2K neutrino experiment in Japan said, “OPERA have now addressed one of the community’s biggest concerns, but given the revolutionary nature of the claim we must apply an extremely high standard of proof. Science consists of that which can be reproduced, so until some other experiment sees this effect it remains an interesting indication rather than a discovery.”
The full press release (link opens in a new window) is available on the Italian Institute for Nuclear Physics (INFN) web site.
STFC is the UK sponsor of particle physics and manages the UK subscription to CERN.
More information on the facilities and experiments mentioned is available on the following web sites: