A bstract We analyze so-called generalized Veneziano and Virasoro amplitudes. Under some physical assumptions, we find that their spectra must satisfy an over-determined set of non-linear recursion relations. The relation for the amplitudes can be solved analytically yields a two-parameter family which includes amplitude, one-parameter Coon amplitudes, larger with infinite tower spins at each m...

We find the complete set of conditions satisfied by forward $2\to2$ scattering amplitude in unitarity and causal theories. These are based on an infinite energy dependent quantities -- arcs which dispersively expressed as moments a positive measure defined at (arbitrarily) higher energies. identify optimal finite subsets constraints, suitable to bound Effective Field Theories (EFTs), any order ...

D-instanton amplitudes suffer from various infrared divergences associated with tachyonic or massless open string modes, leading to ambiguous contribution amplitudes. It has been shown previously that field theory can resolve these ambiguities and lead unambiguous expressions for contributions amplitudes, except an overall normalization constant remains undetermined. In this paper we show theor...