In this letter we show for the first time that the usual CPT-even gauge term of the standard model extension (SME) can be radiatively generated, in a gauge invariant level, in the context of a modified QED endowed with a dimension-five nonminimal coupling term recently proposed in the literature. As a consequence, the existing upper bounds on the coefficients of the tensor $(K_{ F}) $ can be used improve the bounds on the magnitude of the nonminimal coupling, $\lambda(K_{ F}),$ by the factors $10^{ 5}$ or $10^{ 25}.$ The nonminimal coupling also generates higher-order derivative contributions to the gauge field effective action quadratic terms.
Categories: hep-th