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arXiv · 2606.06596

Instanton-Induced Closed-String Amplitudes in Minimal Superstring Theory at Subleading Order

Jyotirmoy Barman·Rishabh Kaushik·Raghu Mahajan·Chitraang Murdia·Ashoke Sen
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Abstract

We compute the disk one-point function, the disk two-point function, and the annulus one-point function of the cosmological constant operator in the type 0A and type 0B minimal superstring theories with (1,1) ZZ instanton boundary conditions. The moduli-space integrals appearing in the disk two-point function and the annulus one-point function have divergences associated with open-string-channel degenerations, which must be regulated using open-closed string field theory. The definition of the string field theory interaction vertices requires a choice of locations for the picture-changing operators, which we specify in detail. After carefully taking into account all contributions, including those from vertical integration, we find that the results precisely match the expectations from DDK-KPZ scaling. Our technical results on the detailed construction of interaction vertices are a first step toward understanding the analogous quantities in the ten-dimensional type IIB superstring, where one also needs to understand how to treat the bosonic and fermionic collective coordinates at subleading order.

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Jyotirmoy Barman, Rishabh Kaushik, Raghu Mahajan, Chitraang Murdia, Ashoke Sen. 2026-06-04. Instanton-Induced Closed-String Amplitudes in Minimal Superstring Theory at Subleading Order. https://arxiv.org/abs/2606.06596

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