NNLO Positivity Bounds on Chiral Perturbation Theory for a General Number of Flavours

Abstract

We present positivity bounds, derived from the principles of analyticity, unitarity and crossing symmetry, that constrain the low-energy constants of chiral perturbation theory. Bounds are produced for 2, 3 or more flavours in meson-meson scattering with equal meson masses, up to and including next-to-next-to-leading order (NNLO), using the second and higher derivatives of the amplitude. We enhance the bounds by using the most general isospin combinations posible (or higher-flavour counterparts thereof) and by analytically integrating the low-energy range of the discontinuities. In addition, we present a powerful and general mathematical framework for efficiently managing large numbers of positivity bounds.

arXiv comment94 pages of which 51 in appendices, 31 figures, 2 tables. Version 2 added to reflect changes (mainly clarifications) done prior to publication in JHEP

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Cited by in corpus (7)

• Crossing Symmetric Spinning S-matrix Bootstrap: EFT bounds
• Bootstrapping Pions at Large $N$
• Cornering Large-$N_c$ QCD with Positivity Bounds
• Moments for positivity: using Drell-Yan data to test positivity bounds and reverse-engineer new physics
• Locality and Analyticity of the Crossing Symmetric Dispersion Relation
• Positivity bounds at one-loop level: the Higgs sector
• Causality constraints on nonlinear supersymmetry