The B-L/Electroweak Hierarchy in Smooth Heterotic Compactifications

TL;DR

This paper details how specific heterotic string compactifications can naturally produce the Standard Model with an additional B-L symmetry, and demonstrates the radiative breaking of this symmetry leading to a hierarchy consistent with observations.

Contribution

It provides a detailed renormalization group analysis of B-L and electroweak symmetry breaking in heterotic string models, including higher order effects and explicit particle spectra.

Findings

B-L gauge symmetry is radiatively broken with a hierarchy of 10 to 100.

Explicit spectrum of squarks and sleptons is computed.

Higher order effects in tan[beta]^{-1} are included.

Abstract

E8 X E8 heterotic string and M-theory, when appropriately compactified, can give rise to realistic, N=1 supersymmetric particle physics. In particular, the exact matter spectrum of the MSSM, including three right-handed neutrino supermultiplets, one per family, and one pair of Higgs-Higgs conjugate superfields is obtained by compactifying on Calabi-Yau manifolds admitting specific SU(4) vector bundles. These "heterotic standard models" have the SU(3)_{C} X SU(2)_{L} X U(1)_{Y} gauge group of the standard model augmented by an additional gauged U(1)_{B-L}. Their minimal content requires that the B-L gauge symmetry be spontaneously broken by a vacuum expectation value of at least one right-handed sneutrino. In a previous paper, we presented the results of a renormalization group analysis showing that B-L gauge symmetry is indeed radiatively broken with a B-L/electroweak hierarchy of O(10) to O(10^{2}). In this paper, we present the details of that analysis, extending the results to include higher order terms in tan[beta]^{-1} and the explicit spectrum of all squarks and sleptons.