The Skyrme Model Revisited: An Effective Theory Approach and Application to the Pentaquarks

The Skyrme model is reconsidered from an effective theory point of view. Starting with the most general Lagrangian up to including terms of order $p^4$, $N_c$ and $\delta m^2$ ($\delta m\equiv m_s-m$), we obtain new interactions, which have never been discussed in the literature. We obtain the parameter set best fitted to the low-lying baryon masses by taking into account the representation mixing up to $\bm{27}$. A prediction for the mainly anti-decuplet excited nucleon $N'$ and $\Sigma'$ is given.