KKbar molecules with momentum-dependent interactions

Abstract

It is shown that the momentum-dependent kaon-antikaon interactions generated via vector meson exchange from the standard SU_V(3) x SU_A(3) interaction Lagrangian lead to a non-local potential in coordinate space that can be incorporated without approximation into a non-relativistic version of the Bethe-Salpeter wave equation containing a radial-dependent effective kaon mass appearing in a fully symmetrized kinetic energy operator, in addition to a local potential. Estimates of the mass and decay widths of f_0(980) and a_0(980), considered as KKbar molecules of isospin 0 and 1, as well as for K^+K^- atomic bound states (kaonium) are presented, and compared with previous studies of a similar nature. It is argued that without a better knowledge of hadronic form factors it is not possible to distinguish between the molecular versus elementary particle models for the structure of the light scalar mesons.

14 pages, 2 tables, 5 figures. Added subsection on s-channel exchange, additional remarks on the possible effect of gluon exchange, and 1 additional figure

References in corpus (6)

• Two-photon decays of hadronic molecules
• f0(980) meson as a K bar K molecule in a phenomenological Lagrangian approach
• QCD Coulomb gauge approach to hybrid mesons
• Studying the scalar bound states of the $K\bar{K}$ system in the Bethe-Salpeter formalism
• Can experiment distinguish tetraquark scalars, molecules and $\qq$ mesons?
• Calculation of the two-photon decay width of the f_0(980) scalar meson