A symmetry for vanishing cosmological constant in an extra dimensional toy model

TL;DR

This paper proposes a symmetry principle in higher-dimensional models that prevents a bulk cosmological constant and ensures a near-zero 4D cosmological constant, with small deviations arising from symmetry breaking.

Contribution

It introduces a novel symmetry mechanism in extra-dimensional models to naturally suppress the cosmological constant in four dimensions.

Findings

Symmetry forbids bulk cosmological constant in 6D and 10D models.

Symmetry extension prevents 4D cosmological constant from 6D curvature.

Small cosmological constant can result from slight symmetry breaking.

Abstract

We introduce a symmetry principle that forbids a bulk cosmological constant in six and ten dimensions. Then the symmetry is extended so that it insures absence of 4-dimensional cosmological constant induced by the six dimensional curvature scalar, at least, for a class of metrics. A small cosmological constant may be induced by breaking of the symmetry by a small amount.