Axion from Quivers in Type II Superstrings

Abstract

We investigate a string‐inspired axion extension of the standard model obtained from Type II superstrings using quiver method. In the first part, we discuss intersecting Type IIA D6‐branes wrapping non trivial 3‐cycles in the presence of the Peccei‐Quinn symmetry U(1)PQ. Concretely, a complex scalar field ϕ=ρexp(iσfσ), where σ is a stringy axion generates a general fermion Yukawa coupling weighted by a flavor‐dependent power nf taking specific values. Using string theory and standard model data with adequate scales, we show that the corresponding axion window could lie in the allowed range 109GeV≤fσ≤1012GeV matching with the recent cosmological results.