Weak kaon production off the nucleon and Watson's theorem

Theoretical tools for neutrino scattering: interplay between lattice QCD, EFTs, nuclear physics, phenomenology, and neutrino event generators

“…It is common that model builders extend the validity of chiral amplitudes towards high Q 2 by introducing phenomenological form factors [206,[468][469][470][471]. Unitarization, which becomes important as W increases, is absent in tree-level amplitudes but can be partially restored by imposing Watson's theorem in relevant multipoles [479,480]. For neutrino interactions, a complete unitarization in coupled channels has only been implemented by the DCC model [397][398][399] and in the strangeness S = −1 sector within the chiral-unitary approach [481].…”