Tree-level S matrix for $\lambda$-deformed AdS3 strings

Marco Costantino; Silvia Penati; Alessandro Sfondrini

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arXiv · 2606.27846

Tree-level S matrix for $\lambda$-deformed AdS3 strings

Marco Costantino·Silvia Penati·Alessandro Sfondrini

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Abstract

We consider the supersymmetric $\lambda$-deformation of $\text{AdS}_3 \times \text{S}^3 \times \text{T}^4$ superstrings and compute its perturbative bosonic tree-level worldsheet S matrix in the light-cone gauge. For generic values of $0 \leq \lambda < 1$, we show that the worldsheet scattering remains compatible with integrability due to a non-trivial cancellation of non-elastic scattering processes. By contrast, the S matrix becomes ill-defined for $\lambda \to 1$, despite the fact that this limit reproduces the non-Abelian T-dual geometry up to an analytic continuation. This suggests that the $\lambda \to 1$ limit does not capture the full worldsheet dynamics of the T-dual theory.

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Marco Costantino, Silvia Penati, Alessandro Sfondrini. 2026-06-26. Tree-level S matrix for $\lambda$-deformed AdS3 strings. https://arxiv.org/abs/2606.27846

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