Zeta Functions and the Superstring

The superstring amplitude's Mellin transform in energy is computed at fixed momentum transfer. In the forward limit, it is shown that this transformed amplitude reduces to the Riemann zeta function, while for $t\neq 0$ it represents a deformation of $\zeta$. This object exhibits remarkable mathematical properties as a result of physical attributes of the string amplitude. For integer subtractions, the dispersion relation defined by the Mellin transform yields the effective field theory expansion of the string amplitude order by order in $s$ at finite $t$, for which a new closed-form expression is derived.