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.
Journal of High Energy Physics
- Pub Date:
- March 2022
- Chiral Lagrangians;
- Effective Field Theories;
- High Energy Physics - Phenomenology
- 94 pages of which 51 in appendices, 31 figures, 2 tables. Version 2 added to reflect changes (mainly clarifications) done prior to publication in JHEP