Unitarity Constraints for New Physics Induced by dim-6 Operators

Abstract

We compute the helicity amplitudes for boson-boson scattering at high energy due to the operators $\O_{B\Phi}$, $\O_{W\Phi}$ and $\O_{UB}$, and we derive the corresponding unitarity bounds. Thus, we provide relations between the couplings of these operators and the corresponding New Physics thresholds, where either unitarity is saturated or new degrees of freedom are excited. We compare the results with those previously obtained for the operators $\O_W$ and $\O_{UW}$ and we discuss their implications for direct and indirect tests at present and future colliders. The present treatment completes the study of the unitarity constraints for all blind bosonic operators.