Stringent constraints on the scalar K\( \pi\) form factor from analyticity, unitarity and low-energy theorems
- First Online:
- Cite this article as:
- Abbas, G., Ananthanarayan, B., Caprini, I. et al. Eur. Phys. J. A (2010) 44: 175. doi:10.1140/epja/i2010-10969-y
We investigate the scalar K \( \pi\) form factor at low energies by the method of unitarity bounds adapted so as to include information on the phase and modulus along the elastic region of the unitarity cut. Using at input the values of the form factor at t = 0 and the Callan-Treiman point, we obtain stringent constraints on the slope and curvature parameters of the Taylor expansion at the origin. Also, we predict a quite narrow range for the higher-order ChPT corrections at the second Callan-Treiman point.
Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.