Details:
Title  Complete Npoint superstring disk amplitude II. Amplitude and hypergeometric function structure  Author(s)  Carlos R. Mafra, Oliver Schlotterer, Stephan Stieberger  Type  Article in Journal  Abstract  Abstract Using the pure spinor formalism in part I (Mafra et al., preprint [1]) we compute the complete treelevel amplitude of N massless open strings and find a striking simple and compact form in terms of minimal building blocks: the full Npoint amplitude is expressed by a sum over ( N − 3 ) ! Yang–Mills partial subamplitudes each multiplying a multiple Gaussian hypergeometric function. While the former capture the space–time kinematics of the amplitude the latter encode the string effects. This result disguises a lot of structure linking aspects of gauge amplitudes as color and kinematics with properties of generalized Euler integrals. In this part II the structure of the multiple hypergeometric functions is analyzed in detail: their relations to monodromy equations, their minimal basis structure, and methods to determine their poles and transcendentality properties are proposed. Finally, a Gröbner basis analysis provides independent sets of rational functions in the Euler integrals.  ISSN  05503213 
URL 
http://www.sciencedirect.com/science/article/pii/S0550321313002447 
Language  English  Journal  Nuclear Physics B  Volume  873  Number  3  Pages  461  513  Year  2013  Edition  0  Translation 
No  Refereed 
No 
