Angular observables for spin discrimination in boosted diboson final states

TL;DR

This paper explores how angular observables can be used to determine the spin of a heavy diboson resonance in boosted hadronic final states, analyzing the impact of jet substructure techniques and experimental cuts on spin discrimination.

Contribution

It provides a detailed analysis of how jet substructure methods and analysis cuts affect the ability to distinguish the spin of diboson resonances, offering optimized strategies for future discoveries.

Findings

CMS and ATLAS can distinguish spin 0, 1, or 2 resonances at 2σ with 30 fb⁻¹ of 13 TeV data.

Modified cuts can significantly improve spin sensitivity in future analyses.

Analysis of existing ATLAS and CMS cuts shows their impact on discrimination power.

Abstract

We investigate the prospects for spin determination of a heavy diboson resonance using angular observables. Focusing in particular on boosted fully hadronic final states, we detail both the differences in signal efficiencies and distortions of differential distributions resulting from various jet substructure techniques. We treat the 2 TeV diboson excess as a case study, but our results are generally applicable to any future discovery in the diboson channel. Scrutinizing ATLAS and CMS analyses at 8 TeV and 13 TeV, we find that the specific cuts employed in these analyses have a tremendous impact on the discrimination power between different signal hypotheses. We discuss modified cuts that can offer a significant boost to spin sensitivity in a post-discovery era. Even without altered cuts, we show that CMS, and partly also ATLAS, will be able to distinguish between spin 0, 1, or 2 new physics diboson resonances at the $2\sigma$ level with 30 fb$^{-1}$ of 13 TeV data, for our 2 TeV case study.