Open string field theory in lightcone gauge

Abstract: We study covariant open bosonic string field theory in lightcone gauge. When lightcone gauge is well-defined, we find two results. First, the vertices of the gauge-fixed action consist of Mandelstam diagrams with stubs covering specific portions of the moduli spaces of Riemann surfaces. This is true regardless of how the vertices of the original covariant string field theory are constructed (e.g. through minimal area metrics, hyperbolic geometry, and so on). Second, the portions of moduli space covered by gauge-fixed vertices are changed relative those covered by the original covariant vertices. The extra portions are supplied through the exchange of longitudinal degrees of freedom in scattering processes.