Heterotic string sigma models: discrete light cone quantization and its current-current deformation

A bstract We propose a two-dimensional superstring sigma model that defines a self-contained corner of heterotic string theory, whose second quantization is heterotic matrix string theory. This worldsheet theory arises from a BPS decoupling limit that zooms in on the heterotic string, under which the target space geometry becomes non-Lorentzian. This construction generalizes the Gomis-Ooguri formulation of non-relativistic string theory to the heterotic case. We show how such a worldsheet theory provides a first-principles definition of the heterotic string in the discrete light cone quantization via T-duality. By turning on a current-current deformation akin to a $$ T\overline{T} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>T</mml:mi> <mml:mover> <mml:mi>T</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> deformation, the conventional heterotic string theory with a Lorentzian target space is recovered. We analyze the gauge and gravitational anomalies with respect to the lowest-order quantum corrections in the sigma model and show how the worldsheet theory is consistent with non-Lorentzian supergravity in the target space.