Absence of U(1) Anomalous Superamplitudes in $\mathcal{N}\geq 5$ Supergravities

Understand

We list all potential candidates for U(1) anomalous non-local 1-loop 4-point amplitudes and higher loop UV divergences in $\mathcal{N}\geq 5$ supergravities.

• The relevant chiral superinvariants are constructed from linearized chiral superfields and define the corresponding superamplitudes.
• The anomalous amplitudes, of the kind present in $\mathcal{N}=4$, are shown to be absent in $\mathcal{N} \geq 5$.
• In $\mathcal{N}=6$ supergravity the result is deduced from the double-copy $\mathcal{N}=4_{YM} \times (\mathcal{N}=2)_{YM}$ model, whereas in $\mathcal{N}=5,8$ the result on absence of anomalous amplitudes is derived in supergravities as well as in the $(\mathcal{N}=4)_{YM} \times (\mathcal{N}-4)_{YM}$ double-copy models.