Gauge-Stringy Instantons in N=2 U(N) Gauge Theories

TL;DR

This paper introduces gauge-stringy instantons in N=2 U(N) gauge theories using string theory brane setups, revealing a dimensionless moduli measure and calculating instanton contributions to the prepotential.

Contribution

It presents the concept of gauge-stringy instantons with extra zero modes and derives their partition function, extending the understanding of instanton effects in supersymmetric gauge theories.

Findings

The moduli space measure becomes dimensionless when gauge and stringy instanton charges are equal.

The partition function for gauge k-instantons matches the standard ADHM result.

Explicit corrections to the prepotential for instanton charges k=1,2 are calculated.

Abstract

Using D3/D(-1) brane set-up in type IIB string theory we introduce gauge-stringy instantons in N=2 U(N) supersymmetry theories with one matter multiplet in symmetric representation. In addition to the gauge and stringy moduli there exist extra zero modes that we refer to as "gauge-stringy" moduli. We show that the measure of the moduli space in this model becomes dimensionless for arbitary N when the gauge instanton charge k_g is equal to the stringy instanton charge k_s. This property of gauge-stringy instantons leads to having equal contributions from all instanton charges k_s=k_g=k in the effective action. We derive the gauge-stringy instanton partition function and calculate the corrections to the prepotential due to k=1,2 gauge-stringy instanton charges. As a by-product the partition function for gauge k-instanton is obtained which coincides with the result from the standard ADHM construction.