Modeling the small dark energy scale with a quintessential pseudoscalar boson

Abstract

Democracy among the same type of particles is a useful paradigm in studying masses and interactions of particles with supersymmetry(SUSY) or without SUSY. This simple idea predicts the presence of massless particles. We attempt to use one of these massless pseudoscalar particles as generating the cosmological dark energy(DE) potential. To achieve the extremely shallow potential of DE, the pseudoscalar boson is required not to couple to the QCD anomaly. So, we consider two pseudoscalars, one coupling to the QCD anomaly (i.e. QCD axion) and the other not coupling to the QCD anomaly. To obtain these two pseudoscalars, we introduce two approximate global U(1) symmetries to realize them as the pseudo-Goldstone bosons of the spontaneously broken U(1)'s. These global symmetries are dictated by a gravity respected discrete symmetry. Specifically, we consider an S2(L) X S2(R) X Z(10R) example, and attempt to obtain the DE scale in terms of two observed fundamental mass scales, the grand unification scale M(G) and the electroweak scale v(ew).