Magnetic and Axial-Vector Transitions of the Baryon Antidecuplet

We report the recent results of the magnetic transitions and axial-vector transitions of the baryon antidecuplet within the framework of the chiral quark-soliton model. The dynamical model parameters are fixed by experimental data for the magnetic moments of the baryon octet, for the hyperon semileptonic decay constants, and for the singlet axial-vector constant. The transition magnetic moments µΛΣ and µNΔ are well reproduced and other octet-decuplet and octet-antidecuplet transitions are predicted. In particular, the present calculation of µΣΣ* is found to be below the upper bound 0.82µN that the SELEX collaboration measured very recently. The results explains consistently the recent findings of a new N* resonance from the GRAAL and Tohoku LNS group. We also obtain the transition axial-vector constants for the Θ+ →KN from which the decay width of the Θ+ pentaquark baryon is determined as a function of the pion-nucleon sigma term ΣπN. We investigate the dependence of the decay width of the Θ+ on the gA(0), with the gA(0) varied within the range of the experimental uncertainty. We show that a small decay width of the Θ+→KN, i.e. ΓΘKN ≤1 MeV, is compatible with the values of all known semileptonic decays with the generally accepted value of gA(0) ≈0.3 for the proton.