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Particles and Fields


Eur. Phys. J. C 22, 133-148 (2001)
DOI: 10.1007/s1005201O0766

$\pi K$ sum rules and the SU(3) chiral expansion

B. Ananthanarayan1, P. Büttiker2 and B. Moussallam3

1  Centre for Theoretical Studies, Indian Institute of Science, Bangalore 560 012, India
2  Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich, Germany
3  Groupe de Physique Théorique, IPN, Université Paris-Sud, 91406 Orsay Cédex, France

(Received: 22 July 2001 / Published online: 21 September 2001 - © Springer-Verlag / Società Italiana di Fisica 2001 )

Abstract
A recently proposed set of sum rules, based on the pion-kaon scattering amplitudes and their crossing symmetric conjugates are analyzed in detail. A key role is played by the l=0 $\pi\pi\to K\overline K$ amplitude which requires an extrapolation to be performed. It is shown how this is tightly constrained from analyticity, chiral counting and the available experimental data, and its stability is tested. A re-evaluation of the O(p4) chiral couplings L1, L2, L3 is obtained, as well as a new evaluation of the large Nc suppressed coupling L4.



© Società Italiana di Fisica, Springer-Verlag 2001