Published by Institute of Physics Publishing for SISSA Received: November 20, 2006 Revised: January 8, 2007 Accepted: January 9, 2007 Published: January 31, 2007 D-branes at singularities, compactification, and hypercharge JHEP01(2007)107 Matthew Buican,a Dmitry Malyshev,a∗ David R. Morrison,bc Herman Verlindea and Martijn Wijnholtad aDepartment of Physics, Princeton University, Princeton, NJ 08544, U.S.A. bCenter for Geometry and Theoretical Physics, Duke University, Durham, NC 27708, U.S.A. cDepartments of Physics and Mathematics, Univ. of California, Santa Barbara, CA 93106, U.S.A. dMax-Planck-Institut f¨ur Gravitationsphysik, Albert-Einstein-Institut, Potsdam, Germany E-mail:
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[email protected] Abstract: We report on progress towards the construction of SM-like gauge theories on the world-volume of D-branes at a Calabi-Yau singularity. In particular, we work out the topological conditions on the embedding of the singularity inside a compact CY threefold, that select hypercharge as the only light U(1) gauge factor. We apply this insight to the proposed open string realization of the SM of hep-th/0508089, based on a D3-brane at a dP8 singularity, and present a geometric construction of a compact Calabi-Yau threefold with all the required topological properties. Keywords: Intersecting branes models, Superstring Vacua, D-branes. ∗On leave from ITEP Russia, Moscow, B Cheremushkinskaya, 25 °c SISSA 2007 http://jhep.sissa.it/archive/papers/jhep012007107 /jhep012007107.pdf Contents 1. Introduction 1 2. General strategy 2 2.1 D-branes at a CY singularity 3 2.2 Symmetry breaking towards the SSM 6 2.3 Summary 6 3.