Based on extensive feedback from the broader particle physics community on its neutrino time-of-flight measurements presented at CERN on September 23, the OPERA collaboration has rechecked many aspects of its analysis and repeated the experiment, this time using very short beam pulses from CERN. This allowed the extraction time of the protons (which led to generating the neutrino beam), to be measured more precisely.

The new test used pulses of only three nanoseconds long, separated by up to 524 nanoseconds. Some 20 clean neutrino events were measured at the Gran Sasso Laboratory in Italy, and precisely associated with the pulse leaving CERN. CERN claims this new test confirms the accuracy of OPERA’s timing measurement, ruling out one potential source of systematic error.

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, CERN said.

The issue of possible GPS timing inaccuracy was not addressed.

T. Adam et al., Measurement of the neutrino velocity with the OPERA detector in the CNGS beam, Journal of High Energy Physics (JHEP).

Ref.: T. Adam et al., Measurement of the neutrino velocity with the OPERA detector in the CNGS beam, arXiv:1109.4897