The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \pm 0.28 (stat.) \pm 0.30 (sys.)) \times 10-5.
A. Plavin, Y. Kovalev, Y. Kovalev, and S. Troitsky. (2020)cite arxiv:2001.00930Comment: 19 pages, 5 figures, 3 tables; accepted to ApJ; v2: extended discussion, added a figure and electronic table; v3: fixed typo in a source name.
C. Gualda, Y. Ashida, A. Sharma, and H. Thomas. (2021)cite arxiv:2107.08670Comment: Presented at the 37th International Cosmic Ray Conference (ICRC 2021). See arXiv:2107.06966 for all IceCube contributions.
E. Akhmedov. (2019)cite arxiv:1905.10207Comment: 24 pages, 1 figure. v2: title changed, section 4 modified, Appendix B added, references added. v3: section 4 slightly expanded; eq. (B.7) corrected. Final version to be published in JCAP.