String-generated quartic scalar interactions

Abstract

The {\em cutting and sewing} procedure is used for getting two-loop order Feynman diagrams of $\Phi^{4}$-theory with an internal SU(N) symmetry group, starting from tachyon amplitudes of the open bosonic string theory. In a suitably defined field theory limit, we reproduce the field theory amplitudes properly normalized and expressed in the Schwinger parametrization.Comment: 8 pages, 8 figure.eps, JHEP.cls, talk given by R. Marotta at the TMR Conference "Quantum aspects of gauge theories, supersymmetry and unification", Paris, September 199