Effective interactions of the open bosonic string via field theory

Abstract

We describe a method to extract an effective Lagrangian description for open bosonic strings, at zero transcendentality. The method relies on a particular formulation of its scattering amplitudes derived from color-kinematics duality. More precisely, starting from a (DF)2 + YM quantum field theory, we integrate out all the massive degrees of freedom to generate an expansion in the inverse string tension α′. We explicitly compute the Lagrangian terms through $$ \mathcal{O} $$ O (α′4), and target the sector of operators proportional to F4 to all orders in α′.