The coupling of η mesons to quarks and baryons from Ds∗→Dsπ0 decay Original Research Article

The known ratio of the branching fractions for View the MathML source and View the MathML source may be used to extract the coupling of η mesons to strange quarks once the value of the π0–η mixing angle is known. This requires that realistic models for the spectra as well as the magnetic dipole (M1) decays of the heavy-light (View the MathML source) mesons are available. The coupling of η mesons to light quarks may then be estimated using SU(3) flavor symmetry. Applied to the quark model for the baryons, an ηNN pseudovector coupling constant of fηNN=0.35+0.15−0.25 is obtained. If the charm quark couples significantly to the η meson, as is suggested by the decay mode ψ′→J/ψη, then somewhat larger values of fηNN can be obtained. These values are sufficiently small to be consistent with phenomenological analysis of photoproduction of the η on the nucleon and the reaction pp→ppη.