CPT invariance and neutrino physics

TL;DR

This paper reviews the role of CPT invariance in neutrino physics, exploring potential violations and their implications for neutrino oscillations, flavor changes, and cosmic neutrino observations, highlighting the interconnectedness with Lorentz symmetry.

Contribution

It provides a comprehensive guide for non-experts on CPT and Lorentz invariance violations in neutrino physics, summarizing key literature and current research directions.

Findings

Neutrino-antineutrino mass differences as a probe for CPT violation

Resonant flavor change phenomena indicating possible CPT/Lorentz violations

Cosmic neutrino observations as potential evidence for fundamental symmetry violations

Abstract

CPT invariance in neutrino physics has attracted attention after the revival of the hypothetical idea that neutrino and antineutrino might have nonequal masses ($m_{\bar\nu} \neq m_{\nu}$) when realizing neutrino oscillations as a new sensitive phenomenon to search for the violation of this fundamental symmetry. Moreover, the profound relation between the CPT and Lorentz symmetries turns the studies of CPT and Lorentz invariance violations into the {\bf one two-sided} problem. We present a guide for non-experts through the literature on neutrino physics. The basic works are reviewed thoroughly while for the other papers only current results or discussion issues are quoted. The review covers, mostly, oscillations of neutrinos, resonant change of their flavors and cosmic neutrino physics to systematize possible evidences of CPT/Lorentz violation in this sector of the Standard