Implications of Configuration Mixing in The Chiral Quark Model With SU(3) and Axial U(1) Breakings for Nucleon Spin-Flavor Structure

The implications of Chiral Quark Model with SU(3) and axial U(1) symmetry breakings as well as configuration mixing generated by one gluon exchange forces (χQMgcm) are discussed in the context of proton flavor and spin structure as well as the hyperon β-decay data. Apart from reproducing the success of χQM with symmetry breaking, it is able to improve upon the agreement with data in several cases such as, GA/GV , ∆8, < A p 1 > dependent on spin polarization functions and ( 2s̄ u+d), ( 2s̄ ū+d̄ ) and fs involving the quark distribution functions. It is well known that the chiral quark model (χQM) [1, 2, 3] with SU(3) symmetry is not only able to give a fair explanation of “proton spin crisis” [4] but is also able to account for the ū−d̄ asymmetry [5, 6] as well as the existence of significant strange quark content s̄ in the nucleon when the asymmetric octet singlet couplings are taken into account [7]. Further, χQM with SU(3) symmetry is also able to provide fairly satisfactory explanation for various quark flavor contributions to the proton spin [8], baryon magnetic moments [3, 8] as well as the absence of polarizations of the antiquark sea in the nucleon [9, 10] . However, in the case of hyperon decay parameters the predictions of the χQM are not in tune with the data [11], for example, in comparison to the experimental numbers .21 and 2.17 the χQM with SU(3) symmetry predicts f3/f8 and ∆3/∆8 to be 1 3 and 5 3 respectively. It has been shown [9, 12] that when SU(3) breaking effects are taken into consideration within χQM, the predictions of the χQM regarding the above mentioned ratios have much better overlap with the data.