Exact potential and scattering amplitudes from the tachyon non-linear $\beta$-function

E. Coletti, V. Forini, G. Grignani +2

We compute, on the disk, the non-linear tachyon $\beta$-function, ${\beta }^T$, of the open bosonic string theory. ${\beta }^T$ is determined both in an expansion to the third power of the field and…