A Weyl-invariant action for chiral strings and branes

TL;DR

This paper introduces a Weyl-invariant chiral sigma model for p-branes, unifying various models like the Schild string and ambitwistor strings, and explores its potential topological nature.

Contribution

It develops a new Weyl-invariant chiral sigma model for p-branes that generalizes existing models and investigates its BRST symmetry and topological properties.

Findings

The model is manifestly diffeomorphism- and Weyl-invariant.

Construction of the BV master action and BRST operator.

Discussion on the model's potential as a topological field theory.

Abstract

We introduce a sigma model lagrangian generalising a number of new and old models which can be thought of as chiral, including the Schild string, ambitwistor strings, and the recently introduced tensionless AdS twistor strings. This "chiral sigma model" describes maps from a $p$-brane worldvolume into a symplectic space and is manifestly diffeomorphism- and Weyl-invariant despite the absence of a worldvolume metric. Construction of the Batalin-Vilkovisky master action leads to a BRST operator under which the gauge-fixed action is BRST-exact; we discuss whether this implies that the chiral brane sigma model defines a topological field theory.