Phenomenology of heterotic string theory: With emphasis on the B-L/EW hierarchy

E8 × E 8 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 is obtained by compactifying on Calabi-Yau manifolds admitting specific SU(4) vector bundles. These “heterotic standard models” have the SU(3) C × SU(2)L × U(1)Y gauge group of the standard model augmented by an additional gauged U(1) B–L. In this thesis, we report on the phenomenological viability of these compactifications. Through a series of increasingly sophisticated analyses, we consider a wide variety of phenomenological effects and compare them to present experimental bounds. We have found that, given the constraints con- sidered, phenomenologically viable regions of parameter space exist and lead to interesting phenomenology, including exact predictions of new particle mass spectra