General spin analysis from angular correlations in two-body decays
Department of Physics and RIPC, Jeonbuk National University, Jeonju, 54896, Korea
* e-mail: firstname.lastname@example.org
Accepted: 22 November 2019
Published online: 3 February 2020
Determining the spin of any new particle and measuring its couplings to other particles and/or itself are crucial in reconstructing the structure of any quantum field theory containing the particle. A general helicity formalism is employed to describe the polarization of the particle Y in a two-body decay with polarized for the purpose of diagnosing the dynamical properties of three involved particles and for determining their spins altogether. We perform a general and comprehensive analytic analysis with our special focus on grasping fully how to connect the decay helicity amplitudes and decay distributions in the rest frame and those in a laboratory frame with moving with a non-zero velocity through Wick helicity rotation on helicity states and amplitudes. This theoretical framework is demonstrated in a detailed illustrative manner with the Standard Model (SM) processes, the sequential process followed by and the sequential process followed by , and one non-standard decay process of a new vector-like heavy top quark, , followed by . All the useful formulas directly applicable to any combinations of spins and any types of couplings in the two-body decay followed by suitable Y two-body decays processes are collected and described in detail.
© Società Italiana di Fisica (SIF) and Springer-Verlag GmbH Germany, part of Springer Nature, 2020