The coupling of η mesons to quarks and baryons from [formula omitted] decay

Abstract

The known ratio of the branching fractions for D s ∗→D sπ 0 and D s ∗→D sγ may be used to extract the coupling of η mesons to strange quarks once the value of the π 0– 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 ( Q q ̄ ) 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 f ηNN =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 f ηNN 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.