Statistical Distribution of the Vacuum Energy Density in Racetrack K\"ahler Uplift Models in String Theory

Abstract

We study a racetrack model in the presence of the leading alpha'-correction in flux compactification in Type IIB string theory, for the purpose of getting conceivable de-Sitter vacua in the large compactified volume approximation. Unlike the K\"ahler Uplift model studied previously, the alpha'-correction is more controllable for the meta-stable de-Sitter vacua in the racetrack case since the constraint on the compactified volume size is very much relaxed. We find that the vacuum energy density \Lambda for de-Sitter vacua approaches zero exponentially as the volume grows. We also analyze properties of the probability distribution of \Lambda in this class of models. As in other cases studied earlier, the probability distribution again peaks sharply at \Lambda=0. We also study the Racetrack K\"ahler Uplift model in the Swiss-Cheese type model.