Gauge couplings in four - dimensional Type I string orbifolds
نویسندگان
چکیده
We compute threshold effects to gauge couplings in four-dimensional Z N orientifold models of type I strings with N = 2 and N = 1 supersymmetry, and study their dependence on the geometric moduli. We also compute the tree-level (disk) couplings of the open sector gauge fields to the twisted closed string moduli of the orbifold in various models and study their effects and that of the one-loop threshold corrections on gauge coupling unification. We interpret the results from the (supergravity) effective theory point of view and comment on the conjectured heterotic-type I duality.
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