Journal Article

Massive and massless spin-2 scattering and asymptotic superluminality

Hinterbichler, Kurt, Bonifacio, James, Joyce, Austin, Rosen, Rachel A.

2018

Overview

A bstract We constrain theories of a massive spin-2 particle coupled to a massless spin-2 particle by demanding the absence of a time advance in eikonal scattering. This is an S -matrix consideration that leads to model-independent constraints on the cubic vertices present in the theory. Of the possible cubic vertices for the two spin-2 particles, the requirement of subluminality leaves a particular linear combination of cubic vertices of the Einstein-Hilbert type. Either the cubic vertices must appear in this combination or new physics must enter at a scale parametrically the same as the mass of the massive spin-2 field, modulo some standard caveats. These conclusions imply that there is a one-parameter family of ghost-free bimetric theories of gravity that are consistent with subluminal scattering. When both particles couple to additional matter, subluminality places additional constraints on the matter couplings. We additionally reproduce these constraints by considering classical scattering off of a shockwave background in the ghost-free bimetric theory.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V,Springer Berlin,SpringerOpen
• Subject: Bimetric theories / Classical and Quantum Gravitation / Classical Theories of Gravity / Constraint modelling / Couplings / Effective Field Theories / Elementary Particles / High energy physics / Particle spin / Physics / Physics and Astronomy / PHYSICS OF ELEMENTARY PARTICLES AND FIELDS / Quantum Field Theories / Quantum Field Theory / Quantum Physics / Regular Article - Theoretical Physics / Relativity Theory / Scattering / Scattering Amplitudes / String Theory