String-induced Yang-Mills coupling to self-dual gravity

TL;DR

This paper derives a (2+2)-dimensional target space action for self-dual gravity and Yang-Mills fields from N=2 string amplitudes, revealing novel stringy couplings and a covariant hyperspace formulation.

Contribution

It introduces a new effective field theory with string-derived couplings for self-dual gravity and Yang-Mills in (2+2) dimensions, including higher-spin states.

Findings

Derived the target space action from N=2 string amplitudes.

Identified novel stringy couplings among self-dual fields.

Presented a covariant hyperspace description of the theory.

Abstract

By considering N=2 string amplitudes we determine the (2+2)-dimensional target space action for the physical degrees of freedom: self-dual gravity and self-dual Yang-Mills, together with their respective infinite towers of higher-spin inequivalent picture states. Novel `stringy' couplings amongst these fields are essential ingredients of an action principle for the effective target space field theory. We discuss the covariant description of this theory in terms of self-dual fields on a hyperspace parametrised by the target space coordinate and a commuting chiral spinor.