# Little strings on $D_n$ orbifolds

## TL;DR

This paper investigates two classes of 6d little string theories from NS5-branes on $D_n$ singularities, analyzing their gauge theories, T-duality, and partition functions to deepen understanding of their non-perturbative dynamics.

## Contribution

It introduces two families of 2d $
abla(0,4)$ gauge theories describing the worldsheet dynamics of little strings on $D_n$ orbifolds, and establishes their T-duality via BPS spectra analysis.

## Key findings

- Confirmed T-duality of the little string theories.
- Computed supersymmetric partition functions on $ extbf{R}^4 imes T^2$.
- Described gauge theories capturing the little strings' worldsheet dynamics.

## Abstract

We explore two classes of 6d $\mathcal{N}=(1,0)$ little string theories obtained from type IIA/IIB NS5-branes probing $D_n$ singularities. Their tensor branches are described by effective gauge theories whose instanton solitons are macroscopic little strings. We specifically study two families of 2d $\mathcal{N}=(0,4)$ gauge theories which describe at low energy the worldsheet dynamics of the type IIA/IIB little strings. These gauge theories are useful to calculate the supersymmetric partition functions of the little string theories on $\mathbf{R}^4 \times T^2$. We establish the T-duality of the little string theories by utilizing their BPS spectra as a probe.