A recent proposal to associate 60 TeV to 2 PeV IceCube neutrino events with gamma-ray bursts (GRBs) indicates the Lorentz violation of cosmic neutrinos and leads further to the CPT symmetry violation between neutrinos and antineutrinos. Here we find that another 12 northern hemisphere track events possibly correlated with GRBs from three-year IceCube data satisfy the same regularity at a lower energy scale around 1 TeV. The combined fitting indicates a Lorentz violation scale E LV = (6.4 ± 1.5) × 10 17 GeV and an intrinsic time difference ∆t in = (−2.8 ± 0.7) × 10 2 s, from which we find an earlier emission of neutrinos than photons at the GRB source. We also suggest analyzing neutrino events detected a few minutes before the GRB trigger time to test the CPT violation of ultrahigh-energy neutrinos.

No abstract

Recent studies on the high-energy photons from gamma-ray bursts (GRBs) suggested a light speed variation v(E) = c(1 − E/ELV) with ELV = 3.6 × 10 17 GeV. We check this speed variation from previous observations on light curves of three active galactic nuclei (AGNs), namely Markarian 421 (Mrk 421), Markarian 501 (Mrk 501) and PKS 2155-304. We show that several phenomena related to the light curves of these AGNs can serve as the supports for the light speed variation determined from GRBs.