We introduce a helicity-chirality spinor formalism to describe scattering amplitudes for particles of any masses and spins. The massive spin-spinors introduced by Arkani-hamed-Huang-Huang have been extended to the spin/helicity-transversality spinors, in which a new quantum number transversality, closely related to chirality, is introduced by extending the Poincare symmetry. The massive helicity-chirality amplitudes can be written by the large and small components of massless spinors $λ$ and $η$ following the $λ\sim \sqrt{E}, η\sim \mathbf{m}/\sqrt{E}$ expansion order by order, which formulate the power counting rules of a large energy effective theory. Diagrammatically the mass expansion in amplitudes originates from the on-shell mass insertion: the helicity flip and chirality flip, which completely determines the three-point massive amplitudes. From the chirality-helicity unification at the UV, any massive helicity-chirality amplitude can be one-to-one corresponded to massless helicity amplitudes with (without) additional Higgs insertion. This UV-IR correspondence explains the mass enhancement in the weak decay processes $π^+ \to μ^+ ν$ and $t \to W^+ b$, and isolates the correct UV of the three-point massive QED $F\bar{F}γ$ amplitudes in Arkani-hamed-Huang-Huang formalism. From massless-massive correspondence, the massless on-shell techniques can be utilized to construct higher-point massive amplitudes.
Massless-Massive Amplitude Correspondence I: Helicity-chirality Matching and On-shell Higgsing
Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；Hangzhou Institute for Advanced Study, UCAS（中国科学院大学杭州高等研究院）；International Center for Theoretical Physics Asia-Pacific（亚太理论物理中心）；Chinese University of Hong Kong, Shenzhen（香港中文大学（深圳））
Massless-Massive Amplitude Correspondence II: Constructive Massive Amplitudes in Standard Model
Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；School of Science and Engineering, Chinese University of Hong Kong, Shenzhen（香港中文大学（深圳）理工学院）；Hangzhou Institute for Advanced Study, UCAS（杭州高等研究院，中国科学院大学）；International Center for Theoretical Physics Asia-Pacific（亚太理论物理中心）
