Moving unstable particles and special relativity

TL;DR

This paper demonstrates that in relativistic quantum theory, the decay probability of unstable particles varies with the observer's frame due to dynamical boosts, challenging the notion of invariance under Lorentz transformations.

Contribution

It provides a theoretical proof that boost transformations affect decay probabilities of unstable particles, revealing a subtle relativistic effect previously considered negligible.

Findings

Decay probability depends on the observer's frame of reference.

Different observers may perceive different internal structures of the same unstable particle.

The effect is too small to be detected with current experimental precision.

Abstract

In Poincare-Wigner-Dirac theory of relativistic interactions, boosts are dynamical. This means that - just like time translations - boost transformations have non-trivial effect on internal variables of interacting systems. This is different from space translations and rotations, whose actions are always universal, trivial and interaction-independent. Applying this theory to unstable particles viewed from a moving reference frame, we prove that the decay probability cannot be invariant with respect to boosts. Different moving observers may see different internal compositions of the same unstable particle. Unfortunately, this effect is too small to be noticeable in modern experiments.