Some tree-level string amplitudes in the NSR formalism

• Published in: The journal of high energy physics Vol. 2015; no. 12; pp. 1 - 48
• Main Authors: Becker, Katrin, Becker, Melanie, Melnikov, Ilarion V., Robbins, Daniel, Royston, Andrew B.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2015; Springer Nature B.V
• Subjects: Amplitudes; Bosons; Classical and Quantum Gravitation; Elementary Particles; Fermions; Formalism; Gluons; High energy physics; Mathematical analysis; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Scattering amplitude; String Theory; Strings; Scattering Amplitudes; Superstrings and Heterotic Strings
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP12(2015)010

A bstract We calculate tree level scattering amplitudes for open strings using the NSR formalism. We present a streamlined symmetry-based and pedagogical approach to the computations, which we first develop by checking two-, three-, and four-point functions involving bosons and fermions. We calculate the five-point amplitude for massless gluons and find agreement with an earlier result by Brandt, Machado and Medina. We then compute the five-point amplitudes involving two and four fermions respectively, the general form of which has not been previously obtained in the NSR formalism. The results nicely confirm expectations from the supersymmetric F 4 effective action. Finally we use the prescription of Kawai, Lewellen and Tye (KLT) to compute the amplitudes for the closed string sector.