Disentangling the Spin-Parity of a Resonance via the Gold-Plated Decay Mode

Understand

Searching for new resonances and finding out their properties is an essential part of any existing or future particle physics experiment.

• The nature of a new resonance is characterized by its spin, charge conjugation, parity, and its couplings with the existing particles of the Standard Model.
• If a new resonance is found in the four lepton final state produced via two intermediate $Z$ bosons, the resonance could be a new heavy scalar or a $Z'$ boson or even a higher spin particle.
• In such cases the step by step methodology as enunciated in this paper can be followed to determine the spin, parity and the coupling to two $Z$ bosons of the parent particles, in a fully model-independent way.