Two Hundred Heterotic Standard Models on Smooth Calabi-Yau Threefolds

TL;DR

This paper constructs over 200 heterotic string models on smooth Calabi-Yau threefolds that replicate the MSSM spectrum, exploring their gauge symmetries and phenomenological implications for particle physics.

Contribution

It systematically generates a large database of heterotic models with MSSM-like spectra on smooth Calabi-Yau threefolds, including analysis of gauge symmetries and phenomenology.

Findings

Over 200 models with MSSM spectrum constructed

Presence of anomalous and massless U(1) symmetries analyzed

Rich phenomenological features including Yukawa couplings and proton stability

Abstract

We construct heterotic standard models by compactifying on smooth Calabi-Yau three-folds in the presence of purely Abelian internal gauge fields. A systematic search over complete intersection Calabi-Yau manifolds with less than six Kahler parameters leads to over 200 such models which we present. Each of these models has precisely the matter spectrum of the MSSM, at least one pair of Higgs doublets, the standard model gauge group and no exotics. For about 100 of these models there are, naively, four additional U(1) symmetries, however these are Green-Schwarz anomalous and, hence, massive. In the remaining cases, three U(1) symmetries are anomalous while the fourth, massless one can be spontaneously broken by singlet vacuum expectation values. The presence of additional global U(1) symmetries, together with the possibility of switching on singlet vacuum expectation values, leads to a rich phenomenology which is illustrated for a particular example. Our database of standard models, which can be further enlarged by simply extending the computer-based search, allows for a detailed and systematic phenomenological analysis of string standard models, covering issues such as the structure of Yukawa couplings, R-parity violation, proton stability and neutrino masses.