Are OPERA neutrinos faster than light because of non-inertial reference frames?

INAF – Astronomical Observatory of Padova, Italy
e-mail: claudio.germana@gmail.com

Received: 26 December 2011
Accepted: 15 January 2012

Abstract

Context. Recent results from the OPERA experiment reported a neutrino beam traveling faster than light. The challenging experiment measured the neutrino time of flight (TOF) over a baseline from the CERN to the Gran Sasso site, concluding that the neutrino beam arrives  ~60 ns earlier than a light ray would do. Because the result, if confirmed, has an enormous impact on science, it might be worth double-checking the time definitions with respect to the non-inertial system in which the neutrino travel time was measured. An observer with a clock measuring the proper time τ free of non-inertial effects is the one located at the solar system barycenter (SSB).

Aims. Potential problems in the OPERA data analysis connected with the definition of the reference frame and time synchronization are emphasized. We aim to investigate the synchronization of non-inertial clocks on Earth by relating this time to the proper time of an inertial observer at SSB.

Methods. The Tempo2 software was used to time-stamp events observed on the geoid with respect to the SSB inertial observer time.

Results. Neutrino results from OPERA might carry the fingerprint of non-inertial effects because they are timed by terrestrial clocks. The CERN-Gran Sasso clock synchronization is accomplished by applying corrections that depend on special and general relativistic time dilation effects at the clocks, depending on the position of the clocks in the solar system gravitational well. As a consequence, TOF distributions are centered on values shorter by tens of nanoseconds than expected, integrating over a period from April to December, longer if otherwise. It is worth remarking that the OPERA runs have always been carried out from April/May to November.

Conclusions. If the analysis by Tempo2 holds for the OPERA experiment, the excellent measurement by the OPERA collaboration will turn into a proof of the general relativity theory in a weak field approximation. The analysis presented here is falsifiable because it predicts that performing the experiment from January to March/April, the neutrino beam will be detected to arrive  ~50 ns later than light.