Non-abelian Z-theory: Berends-Giele recursion for the α -expansion of disk integrals

  • Carlos R. MafraEmail author
  • Oliver Schlotterer
Open Access
Regular Article - Theoretical Physics


We present a recursive method to calculate the α -expansion of disk integrals arising in tree-level scattering of open strings which resembles the approach of Berends and Giele to gluon amplitudes. Following an earlier interpretation of disk integrals as doubly partial amplitudes of an effective theory of scalars dubbed as Z-theory, we pinpoint the equation of motion of Z-theory from the Berends-Giele recursion for its tree amplitudes. A computer implementation of this method including explicit results for the recursion up to order α 7 is made available on the website


Effective field theories Superspaces Superstrings and Heterotic Strings 


Open Access

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© The Author(s) 2017

Authors and Affiliations

  1. 1.STAG Research Centre and Mathematical SciencesUniversity of SouthamptonSouthamptonU.K.
  2. 2.Institute for Advanced StudySchool of Natural SciencesPrincetonU.S.A.
  3. 3.Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-InstitutPotsdamGermany

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