Exploring transcendentality in superstring amplitudes

Covariant Multiloop Superstring Amplitudes

Talk given at Strings 2004 In these proceedings, the multiloop amplitude prescription using the super-Poincaré invariant pure spinor formalism for the superstring is reviewed. Unlike the RNS prescription , there is no sum over spin structures and surface terms coming from the boundary of moduli space can be ignored. Massless N-point multiloop amplitudes vanish for N < 4, which implies (with two...

Remarks on Superstring Amplitudes in Higher Genus

Very recently, Grushevsky continued D’Hoker and Phong’s program of finding the chiral superstring measure from first principles by constructing modular forms satisfying certain factorization constraints. He has proposed an ansatz in genus 4 and conjectured a possible formula for the superstring measure in any genus, subject to the condition that certain modular forms admit holomorphic roots. In...

Annulus Amplitudes in the Minimal Superstring

We study the annulus amplitudes in the (2, 4) minimal superstring theory using the continuum worldsheet approach. Our results reproduce the semiclassical behavior of the wavefunctions of FZZT-branes recently studied in hep-th/0412315 using the dual matrix model. We also study the multi-point functions of neutral FZZT-branes and find the agreement between their semiclassical limit and the worlds...

Topological Amplitudes in Heterotic Superstring Theory ⋆

We show that certain heterotic string amplitudes are given in terms of correlators of the twisted topological (2,0) SCFT, corresponding to the internal sector of the N = 1 spacetime supersymmetric background. The genus g topological partition function F g corresponds to a term in the effective action of the form W 2g , where W is the gauge or gravitational superfield. We study also recursion re...

Scattering amplitudes in open superstring theory