New class of Proca interactions

Understand

We propose a new class of Proca interactions that enjoy a non-trivial constraint and hence propagates the correct number of degrees of freedom for a healthy massive spin-1 field.

• We show that the scattering amplitudes always differ from those of the Generalized Proca.
• This implies that the new class of interactions proposed here are genuinely different from the Generalized Proca and there can be no local field redefinitions between the two.
• In curved spacetime, massive gravity is the natural covariantization but we show how other classes of covariantizations can be considered.