New Selection Rules from Angular Momentum Conservation [article]

Minyuan Jiang, Jing Shu, Ming-Lei Xiao, Yu-Hui Zheng
2020 arXiv   pre-print
We derive the generalized partial wave expansion for M → N scattering amplitude in terms of spinor helicity variables. The basis amplitudes of the expansion with definite angular momentum j consist of the Poincare Clebsch-Gordan coefficients, while j constrains the UV physics that could generate the corresponding operators at tree level. Moreover, we obtain a series of selection rules that restrict the anomalous dimension matrix of effective operators and the way how effective operators contribute to some 2 → N amplitudes at the loop level.
arXiv:2001.04481v1 fatcat:6u3boecxkfh7foogfhklpvapsu