Coupled channel study of a0 resonances

Abstract

A coupled channel model of the a 0 (980) and a 0 (1450) resonances has been constructed using the separable πη and KK interactions. We have shown that two S-matrix poles corresponding to the a 0 (980) meson have significantly different widths in the complex energy plane. The KK to πη branching ratio, predicted in our model near the a 0 (1450) mass, is in agreement with the result of the Crystal Barrel Collaboration. The KK interaction in the S-wave isovector state is not sufficiently attractive to create a bound a 0 (980) meson.

Pion-eta scalar-isovector 3-coupled channel amplitude fitted to branching ratios and threshold plus subthreshold parameters

“…Several years ago it very well described the three coupled channel interactions (ππ, KK and σσ) in the scalar-isoscalar channel (0 + 0 ++ ) [5]. Similar two channel analysis has been presented for the coupled πη and KK channels in the scalarisovector channel [6]. Four parameters of the separable potential has been calculated analytically using four constraints being positions of poles of the a 0 (980) and a 0 (1450) resonances.…”

“…Figures 1-9 present phase shifts, inelasticities and cross sections for found amplitude. If possible they are compared with the corresponding ones for the 2-channel amplitude [6].…”

Coupled channel model of the scalar isovector meson photoproduction

“…To obtain the final state rescattering amplitudes one solves the coupled channel Lippman-Schwinger equations which in momentum space read [5][6][7] q|T |k = q|V|k…”

“…So, to evaluate the model parameters we combine the information on the location of resonance poles in the complex momenta planes with the values of known a 0 (980) branching fractions and amplitude threshold parameters. This approach is the extension of the method used in [7]. One must be aware, however, that the quantities used to constrain model parameters are burdened with large uncertainties which impacts the accuracy of model predictions.…”

Strong interaction between kaons in the reactions e+e−→K+KLeśniak1, Sobczuk2, Silarski3 et al. 2018Phys. Rev. D0000View full textAdd to dashboardCite

“…Transition amplitudes of the reactions coupled to the K + K − channel were described, for example, in Refs. [48][49][50][51]. As it will be shown later, they can be incorporated in a more general scheme taking into account all the relevant channels.…”