Production and Backreaction of Spin-2 Particles of $SU(2)$ Gauge Field during Inflation

Understand

Primordial SU(2) gauge fields with an isotropic background lead to the production of spin-2 particles during inflation.

• We provide a unified formalism to compute this effect in all of the inflation models with isotropic SU(2) gauge fields such as Gauge-flation and Chromo-Natural inflation with and without spectator axion fields or the mass of the gauge field from the Higgs mechanism.
• First, we calculate the number and energy densities of the spin-2 particles.
• We then obtain exact analytical formulae for their backreaction on the background equations of motion of SU(2) and axion fields in (quasi) de Sitter expansion, which were calculated only numerically for one particular model in the literature.