Optimizing Polar Angle Asymmetry Observables at Colliders

TL;DR

This paper introduces optimized angular asymmetry observables using weighted integrals over polar angles to improve spin identification of new bosons at colliders, especially with limited data samples.

Contribution

It generalizes the center-edge asymmetry by employing simple weight functions, enhancing spin discrimination for various boson spins in collider experiments.

Findings

Weighted asymmetries improve spin discrimination.

Optimal power n depends on decay symmetry.

Method effective for limited event samples.

Abstract

Angular asymmetries are simple, intuitive, model-independent observables used to identify spins of new elementary particles. In the case of Drell-Yan-like boson resonances, we generalize the well-known center-edge angular asymmetry to optimize spin identification when only a limited sample of events is available. By choosing simple weight functions in integrals over the polar angle theta, such as cos theta to the nth power, we can improve spin discrimination significantly in production and decays of spin 0, 1, and 2 bosons. The power n can be tuned in particular cases, but n=2 (n=1) works well for any forward-backward symmetric (non-symmetric) decay to massless particles.