SFVdSB/SFVdSB_Option_A__Charged_Sector_Mapping__Sign_of_the_Quartic_Photon_Term: SFVdSB Option A: Charged Sector Mapping - Sign of the Quartic Photon Term

This note accompanies the main SFV/dSB "Option A" gauge-localization paper by (i) establishing the mapping of the effective Lorentz-violating (LIV) operator to a standard photononly EFT used in astrophysical bounds, (ii) showing that the charged sector remains Lorentzinvariant at tree level in the minimal SFV/dSB interpretation of the matter sector and that radiative "percolation" into charged dispersion is parametrically suppressed, and (iii) deriving the sign of the quartic correction to the photon dispersion implied by the Option A heavymode reduction.