High Energy Theory Informal Seminar - IAS - Tomasz Taylor, Northeastern U. - Superstring Amplitudes as a Mellin Transform of Supergravity

Tue, Mar 26, 2013, 1:30 pm to 2:30 pm
Bloomberg Lecture Hall - Institute for Advanced Study
At the tree level, the maximally helicity violating amplitudes of N gauge bosons in open superstring theoryand of N gravitons in supergravity are known to have simple representations in terms of tree graphs.For superstrings, the graphs encode integral representations of certain generalized hypergeometric functions of kinematic invariants while for supergravity, they represent specific kinematic expressions constructed from spinor-helicity variables. We establish asuperstring/supergravity correspondence for this class of amplitudes, by constructing a mapping between thepositions of gauge boson vertices at the disk boundary and the helicity spinors associated to gravitons. After replacing vertex positions by a larger set ofN(N-3)/2 coordinates, the superstring amplitudes become (multiple) Mellin transforms of supergravity amplitudes, from the projective space into the dual Mellin space of N(N-3)/2 kinematic invariants. We elaborate on the properties of Mellin and inverse Mellin transformsin the framework of superstring/supergravity correspondence.