Tower Exchange inλϕ3Theory

We study the asymptotic behavior of two-tower exchange with linked ends in ${\varphi }^3$ theory using Feynman parameter techniques. We present a new result for the asymptotic behavior of the Mandelstam graph and note that only this graph contributes for the two-tower case. We generalize the above to the $N$-tower case and find the eikonal form.