CHIRAL CONSTITUENT QUARK MODEL AND THE COUPLING STRENGTH OF η′

Abstract

Using the latest data pertaining to [Formula: see text] asymmetry and the spin polarization functions, detailed implications of the possible values of the coupling strength of the singlet Goldstone boson η′ have been investigated in the χCQM with configuration mixing. Using Δu, Δ3, [Formula: see text] and [Formula: see text], the possible ranges of the coupling parameters a, α2a, β2a and ζ2a, representing respectively the probabilities of fluctuations to pions, K, η and η′, are shown to be 0.10 ≲ a ≲ 0.14, 0.2 ≲ α ≲ 0.5, 0.2 ≲ β ≲ 0.7 and 0.10 ≲|ζ|≲ 0.70. To further constrain the coupling strength of η′, detailed fits have been obtained for spin polarization functions, quark distribution functions and baryon octet magnetic moments corresponding to the following sets of parameters: a = 0.1, α = 0.4, β = 0.7, |ζ| = 0.65 (Case I); a = 0.1, α = 0.4, β = 0.6, |ζ| = 0.70 (Case II); a = 0.14, α = 0.4, β = 0.2, ζ = 0 (Case III) and a = 0.13, α = β = 0.45, |ζ| = 0.10 (Case IV). Case I represents the calculations where a is fixed to be 0.1, in accordance with earlier calculations, whereas other parameters are treated free and the Case IV represents our best fit. The fits clearly establish that a small nonzero value of the coupling of η′ is preferred over the higher values of η′ as well as when ζ = 0, the latter implying the absence of η′ from the dynamics of χCQM. Our best fit achieves an overall excellent fit to the data, in particular the fit for Δu, Δd, Δ8 as well as the magnetic moments μn, μΣ-, μΣ+ and μΞ- is almost perfect, the μΞ- being a difficult case for most of the similar calculations.