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arXiv · 0709.1805

New twist field couplings from the partition function for multiply wrapped D-branes

Dario Duo·Rodolfo Russo·Stefano Sciuto
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Abstract

We consider toroidal compactifications of bosonic string theory with particular regard to the phases (cocycles) necessary for a consistent definition of the vertex operators, the boundary states and the T-duality rules. We use these ingredients to compute the planar multi-loop partition function describing the interaction among magnetized or intersecting D-branes, also in presence of open string moduli. It turns out that unitarity in the open string channel crucially depends on the presence of the cocycles. We then focus on the 2-loop case and study the degeneration limit where this partition function is directly related to the tree-level 3-point correlators between twist fields. These correlators represent the main ingredient in the computation of Yukawa couplings and other terms in the effective action for D-brane phenomenological models. By factorizing the 2-loop partition function we are able to compute the 3-point couplings for abelian twist fields on generic non-factorized tori, thus generalizing previous expressions valid for the 2-torus.

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Dario Duo, Rodolfo Russo, Stefano Sciuto. 2007-10-08. New twist field couplings from the partition function for multiply wrapped D-branes. https://doi.org/10.1088/1126-6708%2F2007%2F12%2F042

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