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Photo of Johan Bijnens

Johan Bijnens

Professor

Photo of Johan Bijnens

Higher-order tree-level amplitudes in the nonlinear sigma model

Author

  • Johan Bijnens
  • Karol Kampf
  • Mattias Sjä

Summary, in English

We present a generalisation of the flavour-ordering method applied to the chiral nonlinear sigma model with any number of flavours. We use an extended Lagrangian with terms containing any number of derivatives, organised in a power-counting hierarchy. The method allows diagrammatic computations at tree-level with any number of legs at any order in the power-counting. Using an automated implementation of the method, we calculate amplitudes ranging from 12 legs at leading order, O(p2), to 6 legs at next-to- next-to-next-to-leading order, O(p8). In addition to this, we generalise several properties of amplitudes in the nonlinear sigma model to higher orders. These include the double soft limit and the uniqueness of stripped amplitudes.

Department/s

  • Theoretical Particle Physics

Publishing year

2019

Language

English

Publication/Series

Journal of High Energy Physics

Volume

2019

Issue

11

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Keywords

  • Chiral Lagrangians
  • Effective Field Theories
  • Scattering Amplitudes
  • Spon- taneous Symmetry Breaking

Status

Published

ISBN/ISSN/Other

  • ISSN: 1029-8479