Implications of η Coupling In The Chiral Constituent Quark Model

Using the latest data pertaining to ū− d̄ 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 ∆u, ∆3, ū− d̄ and ū/d̄, 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 found. 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. The fits clearly establish that a small non-zero 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 for ∆u, ∆d, ∆8 as well as the magnetic moments μn, μΣ− , μΣ+ and μΞ− . The implications of η ′ on the gluon polarization have also been investigated. The chiral constituent quark model (χCQM), as formulated by Manohar and Georgi [1], has recently got good deal of attention [2, 3, 4, 5] as it is successful in not only explaining the “proton spin crisis” [6] but is also