Central Charge as the Origin of Holomorphic Effective Action in N=2 Gauge Theory

TL;DR

This paper shows that the holomorphic part of the N=2 U(1) gauge theory effective action originates from minimal coupling to a hypermultiplet with a mass generated by a central charge, linking algebraic structure to effective dynamics.

Contribution

It explicitly demonstrates the role of the central charge in generating the holomorphic effective action in N=2 gauge theories using harmonic superspace techniques.

Findings

Holomorphic effective action arises from minimal coupling to a hypermultiplet.

Central charge induces a mass that breaks U(1)_R symmetry.

Superspace techniques facilitate quantum calculations with central charge.

Abstract

We explicitly demonstrate that the perturbative holomorphic contribution to the off-shell effective action of N=2 U(1) gauge supermultiplet is an entire effect of the minimal coupling to a hypermultiplet with the mass generated by a central charge in N=2 superalgebra. The central charge is induced by a constant vacuum N=2 gauge superfield strength spontaneously breaking the automorphism U(1)_R symmetry of N=2 superalgebra. We use the manifestly off-shell supersymmetric harmonic superspace techniques of quantum calculations with the central charge-massive hypermultiplet propagator.