Phys. Lett. B 822, 136698 (2021) arXiv link
Infrared photons and asymptotic symmetries
Zhengwen Liu1 and Pujian Mao2,*
1 Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
2 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, 135 Yaguan Road, Tianjin 300350, China
* Corresponding Authors: Z. Liu (Email: firstname.lastname@example.org ) P. Mao (Email: email@example.com )
S-matrix elements exhibit universal factorization when multiple infrared photons are emitted in scattering processes. We explicitly show that the leading soft factorization of tree-level amplitudes with the emission of any number of soft photons can be interpreted as the Ward identity of the asymptotic symmetry of gauge theory.