Determining Spin through Quantum Azimuthal-Angle Correlations

TL;DR

This paper proposes a method to determine the spin of new particles in collider experiments by analyzing azimuthal-angle correlations, even when the decay process has ambiguities, enhancing the ability to identify new physics.

Contribution

It introduces a novel approach to extract quantum interference effects from partially reconstructible processes using decay plane correlations in e+ e- collisions.

Findings

Effective spin determination in ambiguous decay processes

Extraction of interference effects via decay plane correlations

Applicable to next-generation collider experiments

Abstract

Determining the spin of new particles is critical in identifying the true theory among various extensions of the Standard Model at the next generation of colliders. Quantum interference between different helicity amplitudes was shown to be effective when the final state is fully reconstructible. However, many interesting new physics processes allow only for partial reconstruction. In this paper, we show how the interference effect can be unambiguously extracted even in processes that have two-fold ambiguity, by considering the correlation between two decay planes in e+ e- collisions.