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arXiv · 0801.0149

S-duality Action on Discrete T-duality Invariants

Shamik Banerjee·Ashoke Sen
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Abstract

In heterotic string theory compactified on T^6, the T-duality orbits of dyons of charge (Q,P) are characterized by O(6,22;R) invariants Q^2, P^2 and Q.P together with a set of invariants of the discrete T-duality group O(6,22;Z). We study the action of S-duality group on the discrete T-duality invariants and study its consequence for the dyon degeneracy formula. In particular we find that for dyons with torsion r, the degeneracy formula, expressed as a function of Q^2, P^2 and Q.P, is required to be manifestly invariant under only a subgroup of the S-duality group. This subgroup is isomorphic to Γ^0(r). Our analysis also shows that for a given torsion r, all other discrete T-duality invariants are characterized by the elements of the coset SL(2,Z)/Γ^0(r).

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Shamik Banerjee, Ashoke Sen. 2007-12-30. S-duality Action on Discrete T-duality Invariants. https://doi.org/10.1088/1126-6708%2F2008%2F04%2F012

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