2002/09/04 by Gerald Cleaver, Virendra Desai, Vishal V Desai +8 · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Particle physics theoretical and experimental studies #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.67.026009
published as Phys.Rev. D67 (2003) 026009 · 16 pages. Standard Latex
arxiv created 2002/09/04 · openalex publication_date 2003/01/30 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recently Giedt discussed a mechanism, entitled optical unification, whereby string scale unification is facilitated via exotic matter with intermediate scale mass. This mechanism guarantees that a virtual minimal supersymmetric standard model unification below the string scale is extrapolated from the running of gauge couplings upward from M_Zo when an intermediate scale desert is assumed. In this paper we explore the possibility of optical unification within the context of weakly coupled heterotic strings. In particular, we investigate this for models of free fermionic construction containing the Nanopoulos-Antoniadis-Hagelin-Ellis (NAHE) set of basis vectors. This class is of particular interest for optical unification, because it provides a standard hypercharge embedding within SO(10), giving the standard kY=(5)/(3) hypercharge level, which was shown necessary for optical unification. We present a NAHE model for which the set of exotic SU(3)C triplet-antitriplet pairs, SU(2)L doublets, and non-Abelian singlets with hypercharge offers the possibility of optical unification. Whether this model can realize optical unification is conditional upon these exotics not receiving Fayet-Iliopoulos (FI) scale masses when a flat direction of scalar vacuum expectation values is nonperturbatively chosen to cancel the FI D term \ensuremathξ generated by the anomalous U(1)-breaking Green-Schwarz-Dine-Seiberg-Witten mechanism. A study of perturbative flat directions and their phenomenological implications for this model is underway.