Axion from Quivers in Type II Superstrings

TL;DR

This paper explores a string-inspired axion model derived from Type II superstrings with quiver methods, analyzing its properties, axion window, and implications for cosmology, including hyperbolic quivers and their moduli.

Contribution

It introduces a novel axion extension of the standard model from Type II superstrings using quiver techniques, linking string theory, axion physics, and cosmological constraints.

Findings

Axion decay constant range matches cosmological bounds (10^9 to 10^12 GeV).

Hyperbolic quivers decouple axion decay constant from string scale.

Fermion Yukawa couplings influenced by flavor-dependent powers.

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 $\phi =\rho exp(\frac{i\sigma}{f_{\sigma}})$, where $\sigma$ is a closed string axion generates a general fermion Yukawa coupling weighted by a flavor-dependent power $n_{f}$ taking specific values. Using string theory and standard model data, we find that the corresponding axion window is in the allowed range $10^{9}GeV\leq f_{\sigma}\leq 10^{12}GeV $ matching with the recent cosmological results. Then, we extend these results to the case of the hyperbolic quiver whose the moduli is related to the stringy axion using root systems of ADE Lie algebras. For the hyperbolic quiver case, we observe that the closed axion decay constant becomes disentangled from the string scale.