Mixing of pentaquark and molecular states
Department of Physics, Nankai University, 300071, Tianjin, P.R. China
2 NCTS and Department of Physics, National Taiwan University, 1067, Taipei, Taiwan, R.O.C
There are experimental evidences for the existence of narrow states Θ + and Θ c with the same quantum numbers of and pentaquarks and also NK (*) and ND (*) molecular states. Their masses deviate from many theoretical estimates of the pure pentaquark and molecular states. In this work we study the possibility that the observed Θ + and Θ c are mixtures of pure pentaquark and molecular states. The mixing parameters are in general related to non-perturbative QCD which are not calculable at present. We determine them by fitting data from known states and then generalize the mechanism to Θ b to predict its mass and width. The mixing mechanism can also naturally explain the narrow width for Θ + and Θ c through destructive interferences, even if the pure pentaquark and molecular states have much larger decay widths. We also briefly discuss the properties of the partner eigenstates of Θ + and Θ c and the possibility of experimentally observe them. Moreover, probable consequences of multi-state mixing are also addressed.
© Springer-Verlag, 2005