Testing Lorentz invariance and CPT symmetry using gamma-ray burst neutrinos

TL;DR

This paper investigates Lorentz and CPT symmetry violations using PeV neutrinos from gamma-ray bursts observed by IceCube, deriving parameters within the SME framework and proposing experimental tests for CPT violation.

Contribution

It provides a detailed analysis of Lorentz and CPT violation parameters based on neutrino data, extending previous hypotheses within the SME framework and suggesting ways to test CPT symmetry.

Findings

Lorentz violation scale estimated at ~6.5×10^{17} GeV.

Neutrino and antineutrino propagation can differ with CPT violation.

Threshold energy constraints affect superluminal neutrino interpretations.

Abstract

A recent work [Y. Huang and B.-Q. Ma, Commun. Phys. {\bf 1}, 62 (2018)] associated all four PeV neutrinos observed by IceCube to gamma-ray bursts (GRBs), and revealed a regularity which indicates a Lorentz violation scale $E_{\rm LV}=(6.5\pm0.4)\times10^{17}$ GeV with opposite sign factors $s=\pm 1$ between neutrinos and antineutrinos. The association of "time delay" and "time advance" events with neutrinos and antineutrinos (or vice versa) is only a hypothesis since the IceCube detector cannot tell the chirality of the neutrinos, and further experimental tests are needed to verify this hypothesis. We derive the values of the CPT-odd Lorentz violating parameters in the standard-model extension (SME) framework, and perform a threshold analysis on the electron-positron pair emission of the superluminal neutrinos (or antineutrinos). We find that different neutrino/antineutrino propagation properties, suggested by Y. Huang and B.-Q. Ma, can be described in the SME framework with both Lorentz invariance and CPT symmetry violation, but with a threshold energy constraint. A viable way on testing the CPT symmetry violation between neutrinos and antineutrinos is suggested.