1997/02/12 by Massimo Bianchi, Bianchi, Massimo
Mathematics · Physics and Astronomy · #Algebraic structures and combinatorial models #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #Nonlinear Waves and Solitons #hep-th
paper · pdf · doi:10.48550/arxiv.hep-th/9702098
11 pages, latex, no figures; contribution to the Proceedings of the XII Italian Conference on General Relativity and Gravitational Physics, Rome, September 1996
arxiv created 1997/02/12 · openalex publication_date 1997/02/12 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Notwithstanding the central role of D-branes in many recently proposed string dualities, several interesting type I vacua have been found without resorting directly to D-brane technology. In this talk, we analyze a three-generation SO(8)xU(12) chiral type I model with N=1 supersymmetry in D=4. It descends from the type IIB compactification on the Z orbifold and requires only Neumann boundary conditions, i.e. only the ubiquitous D9-branes (pan-branes). We also discuss a large class of 6D type I vacua that display rich patterns of Chan-Paton symmetry breaking/enhancement and various numbers of tensor multiplets. Finally, we briefly address issues raised by the conjectured heterotic - type I duality and by the relation between type I vacua and compactifications of the putative F-theory.