A Story of Time Invariance Violation in Neutrino Oscillations

Olivia Bitter

Neutrinos may be everywhere, from the dawn of the universe to your average banana, but key mysteries regarding these ninja-like particles still exist today. One important question that physicists like to ask about neutrinos relates to disentangling the nuances of matter effects, (you can think of this as the simple ordinary matter/medium through which a neutrino travels through), as they play a role in the story of the interplay of fundamental discrete symmetries, such as Charge-Parity Violation (CPV) and Time Invariance Violation (TV) respectively. In fact, addressing the nature of CPV in the leptonic sector is something that is achievable for both current and future accelerator-based long-baseline neutrino oscillation experiments. However, neutrinos propagate through a non-trivial amount of ordinary matter at these experiments, complicating the picture. This, along with the fact that we do not have the capability to build experiments in an anti-Earth, requires a careful treatment of the type of CPV comparison that we are making. Therefore, by following the assumption of CPT as a fundamental symmetry, one can pivot the discussion to that of time invariance violation (TV) in matter-based neutrino oscillations instead. By revisiting the pedagogical study of TV, this talk will focus on providing potential consequences in the case where we have a new beam source (i.e. muon storage rings) which would allow for an experiment to make TV channel comparisons. We discuss the above for different types of matter potential profiles, in an effort to distinguish between intrinsic and matted-induced TV, if at all, in neutrino oscillation probabilities.