Massive Higher Spins: Effective Theory and Consistency

Understand

We construct the effective field theory for a single massive higher-spin particle in flat spacetime.

• Positivity bounds of the S-matrix force the cutoff of the theory to be well below the naive strong-coupling scale, forbid any potential and make therefore higher-derivative operators important even at low energy.
• As interesting application, we discuss in detail the massive spin-3 theory and show that an extended Galileon-like symmetry of the longitudinal modes, even with spin, emerges at high energy.