Eur. Phys. J. C 25, 259-276 (2002)
DOI: 10.1007/s10052-002-0975-1
Analysis of the pion-kaon sigma term and related topics
M. Frink, B. Kubis and U.-G. MeißnerForschungszentrum Jülich, Institut für Kernphysik (Theorie), 52425 Jülich, Germany
(Received: 21 March 2002 / Published online: 5 July 2002)
Abstract
We calculate the one-loop contributions to the
difference
between the isoscalar on-shell pion-kaon
scattering amplitude at the Cheng-Dashen point and
the scalar form factor
in the framework
of three
flavor chiral perturbation theory. These corrections turn out
to be
small. This is further sharpened by treating the kaons as heavy
fields (two flavor chiral perturbation theory). We also analyze
the two-loop corrections to the kaon scalar form factor based
on a dispersive
technique. We find that these corrections are smaller than in
the
comparable case of the scalar form factor of the pion. This is
related
to the weaker final state interactions in the pion-kaon channel.
© Società Italiana di Fisica, Springer-Verlag 2002