%0 Journal Article
%T Form factors of the isovector scalar current and the eta pi scattering phase shifts
%A Albaladejo, M.
%A Moussallam, B.
%J European Physical Journal C
%D 2015
%V 75
%N 10
%I Springer
%@ 1434-6044
%G English
%F Albaladejo+Moussallam2015
%O WOS:000362951600001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=2415), last updated on Thu, 05 Nov 2015 12:12:07 +0000
%X A model for S-wave eta pi scattering is proposed which could be realistic in an energy range from threshold up to above 1 GeV, where inelasticity is dominated by the K (K) over bar channel. The T-matrix, satisfying two-channel unitarity, is given in a form which matches the chiral expansion results at order p(4) exactly for the eta pi -> eta pi, eta pi -> K (K) over bar amplitudes and approximately for K (K) over bar -> K (K) over bar. It contains six phenomenological parameters. Asymptotic conditions are imposed which ensure a minimal solution of the Muskhelishvili-Omnes problem, thus allowing one to compute the eta pi and K (K) over bar form factor matrix elements of the I = 1 scalar current from the T-matrix. The phenomenological parameters are determined such as to reproduce the experimental properties of the a(0)(980), a(0)(1450) resonances, as well as the chiral results of the eta pi and K (K) over bar scalar radii, which are predicted to be remarkably small at O(p(4)). This T-matrix model could be used for a unified treatment of the eta pi final-state interaction problem in processes such as eta ' -> eta pi pi, phi -> eta pi gamma or the eta pi initial-state interaction in eta -> 3 pi.
%R 10.1140/epjc/s10052-015-3715-z
%U http://arxiv.org/abs/1507.04526
%U https://doi.org/10.1140/epjc/s10052-015-3715-z
%P 488 - 16pp