R Symmetries in the Landscape

TL;DR

This paper investigates the distribution of R-symmetries in string theory landscapes, finding significant suppression of states with classical R-symmetries but noting the commonality of Z2 R-parity, with implications for phenomenology.

Contribution

It provides a survey of orientifolds in IIB Calabi-Yau compactifications, quantifies the suppression of R-symmetric states, and discusses phenomenological implications of R-parities.

Findings

R-symmetric states are substantially suppressed in the landscape.

Z2 R-parity is a common feature across models.

Implications for cosmology and proton decay are discussed.

Abstract

In the landscape, states with $R$ symmetries at the classical level form a distinct branch, with a potentially interesting phenomenology. Some preliminary analyses suggested that the population of these states would be significantly suppressed. We survey orientifolds of IIB theories compactified on Calabi-Yau spaces based on vanishing polynomials in weighted projective spaces, and find that the suppression is quite substantial. On the other hand, we find that a $Z_2$ R-parity is a common feature in the landscape. We discuss whether the cosmological constant and proton decay or cosmology might select the low energy branch. We include also some remarks on split supersymmetry.