Disentangling the spin-parity of a resonance via the gold-plated decay mode

• Published in: Chinese physics C 2016-03, Vol.40 (3), p.12-28
• Main Authors: Modak, Tanmoy, Sahoo, Dibyakrupa, Sinha, Rahul, Cheng, Hai-Yang, Yuan, Tzu-Chiang
• Format: Article
• Language: English
• Subjects: Bosons; Conjugation; Couplings; Decay; Parents; Parity; Particle spin; Scalars; 共振耦合; 奇偶校验; 标准模型; 玻色子; 粒子物理实验; 自旋宇称; 衰减模式; 镀金
• ISSN: 1674-1137; 0254-3052
• DOI: 10.1088/1674-1137/40/3/033002

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 a 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. In our approach we show how three uni-angular distributions and a few experimentally measurable observables can conclusively tell us about the spin, parity as well as the couplings of the new resonance to two Z bosons. We have performed a numerical analysis to validate our approach and showed how the uni-angular observables can be used to disentangle the spin parity as well as the coupling of the resonance.