Relativistic Calculation of Pentaquark Widths

Abstract

We calculate the widths of the various pentaquarks in a relativistic model in which the pentaquark is considered to be composed of a scalar diquark and a spin 1/2 triquark. We consider both positive and negative parity for the pentaquark. There is a single parameter in our model which we vary and which describes the size of the pentaquark. We obtain quite small widths for the decay Theta^(+) -> N+K^(+) and for Theta_c^0 -> P+D^{*-} consistent with the experimental situation. For the sum of the decay widths for Xi(bar)^(--) -> Xi^(-) + pi^(+) and Xi(bar)^(--) -> Sigma^(-) + K^(-) we find values of the order of 4-8 MeV for pentaquarks of the characteristic size considered in this work. (The experimental situation with respect to te observation of the Xi(bar)^(--) is somewhat uncertain at this time.) We also provide results for the decays N^(+) -> N + pi and N_s^(+) -> Lambda^(0) + K^(+). Our model of confinement plays an important role in our analysis and makes it possible to use Feynman diagrams to describe the decay of the pentaquark.