1999/05/14 by Luis E. Ibáñez, Ibanez, Luis E.
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.hep-ph/9905349
openalex publication_date 1999/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We use compact D=4, N=1, Type IIB orientifolds as a testing ground for recent ideas about precocious gauge coupling unification and a low energy string scale. We find that certain such orientifolds have the interesting property that gauge couplings receive moduli-dependent corrections which mimic the effect of field theoretical logarithmic running. The effective cut-off scale for the logarithmic correction is not Mstring but rather MX=√αMPlanckMc/Mstring, where Mc is the compactification scale. Thus there is just normal logarithmic running up to Mstring and extra moduli dependent corrections which behave as if there was further running to a higher virtual scale MX. In this mechanism a prominent role is played by anomalous U(1)'s with moduli dependent Fayet-Iliopoulos terms. A vanishing FI-term fixes the modulus dependence of the corrected gauge coupling. We discuss possible ways to implement this mechanism in the context of a simple extension of the MSSM.