I will discuss recently derived soft theorems obeyed by scattering amplitudes. For scattering amplitudes involving a class of Goldstone bosons, such as pions, a generalized double-soft theorem is obeyed when the associated quantum field theory possesses a spontaneously broken higher-group symmetry. This theorem can be derived from the algebra of symmetry currents in the quantum field theory. The contribution sensitive to the higher-group structure appears at sub-leading order in the double-soft expansion. Treated within the context of the chiral effective field theory, there are further, non-universal contributions to the sub-leading soft theorem which depend on Wilson coefficients of higher-derivative operators. I will describe how these terms within the soft factors are renormalized at 1-loop, with structure dictated by symmetry and the principles of effective field theory.
John Joseph M. Carrasco
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