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Abstract: We test the validity of the QCD sum rules applied to the meson , by considering a diquark–antidiquark type of current with and with . We find that, with the studied currents, it is possible to find an acceptable Borel window. In such a Borel window we have simultaneously a good OPE convergence and a pole contribution which is bigger than the continuum contribution. We get and for the currents with and , respectively. We conclude that the QCD sum rules results favors quantum numbers for the meson. [Copyright &y& Elsevier]

We consider a [ud]2s¯ current in the QCD sum rule framework to study the mass of the recently observed pentaquark state Θ+(1540), obtaining good agreement with the experimental value. We also study the mass of the pentaquark [ud]2d¯. Our results are compatible with the interpretation of the [ud]2d¯ state as being the Roper resonance N(1440), as suggested by Jaffe and Wilczek. [Copyright &y& Elsevier]