1304.7918 (Rutger H. Boels)

On the field theory expansion of superstring five point amplitudes    [PDF]

Rutger H. Boels

A simple recursive expansion algorithm for the integrals of superstring five point amplitudes in a flat background is given which reduces the expansion to simple symbol(ic) manipulations. This approach can be used for instance to prove the expansion is maximally transcendental to all orders and to verify several conjectures made in recent literature to high order. Starting at order eighteen for instance new identities for products of certain matrices associated to single (odd) zeta values are identified. For closed strings apart from generalities in particular the maximal R-symmetry violating amplitudes in type IIB superstring theory are studied. The obtained expansion of the open string amplitudes reduces the analysis for MRV amplitudes to the classification of completely symmetric polynomials of the external legs, up to momentum conservation. Using Molien's theorem as a counting tool this problem is solved by constructing an explicit nine element basis for this class. This theorem may be of wider interest: as is illustrated at higher points it can be used to calculate dimensions of polynomials of external momenta invariant under any finite group for in principle any number of legs, up to momentum conservation. We comment briefly on extension of the techniques discussed in this paper to higher numbers of legs.

View original: http://arxiv.org/abs/1304.7918