Why a splitting in the final state cannot explain the GSI-Oscillations

TL;DR

This paper argues that the GSI anomaly's oscillations cannot be explained by final state splitting within Standard Model physics, using pedagogical quantum field theory analysis and amplitude methods.

Contribution

It provides a clear, dual-formulation analysis showing that final state splitting alone cannot account for GSI oscillations, challenging common assumptions.

Findings

Decay rate oscillations require initial state coherence

Final state splitting alone cannot produce oscillations

Standard Model physics is insufficient to explain GSI anomaly

Abstract

In this paper, I give a pedagogical discussion of the GSI anomaly. Using two different formulations, namely the intuitive Quantum Field Theory language of the second quantized picture as well as the language of amplitudes, I clear up the analogies and differences between the GSI anomaly and other processes (the Double Slit experiment using photons, $e^+ e^- \to \mu^+ \mu^-$ scattering, and charged pion decay). In both formulations, the conclusion is reached that the decay rate measured at GSI cannot oscillate if only Standard Model physics is involved and the initial hydrogen-like ion is no coherent superposition of more than one state (in case there is no new, yet unknown, mechanism at work). Furthermore, a discussion of the Quantum Beat phenomenon will be given, which is often assumed to be able to cause the observed oscillations. This is, however, not possible for a splitting in the final state only.